材料科学

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[1] arXiv:2508.00972 [中文pdf, pdf, 其他]

标题： 高幅值、空间可变且持续的应变工程2D半导体 显示英文标题

标题： High-magnitude, spatially variable, and sustained strain engineering of 2D semiconductors

Boran Kumral, Peter Serles, Pedro Guerra Demingos, Shuo Yang, Da Bin Kim, Dian Yu, Akhil Nair, Akshat Rastogi, Nima Barri, Md Akibul Islam, Jane Howe, Cristina H Amon, Sjoerd Hoogland, Edward H. Sargent, Chandra Veer Singh, Tobin Filleter

评论： 23页正文，含5张图表和26页补充信息，含13张图表

主题： 材料科学 (cond-mat.mtrl-sci) ; 应用物理 (physics.app-ph)

晶体二维（2D）半导体通常结合了高弹性和平面内强度，使其成为应变诱导调节电子特性的理想材料，类似于在硅电子学中使用的策略。 然而，目前的技术在实现高幅度（>1%）、空间分辨和稳定的应变方面存在不足。 在此，我们通过将单层MoS2转移到使用双光子光刻技术制造的图案化基底上，实现了高达2.2%的双轴拉伸应变，在微米尺度区域内的分辨率约为±0.12%。 所诱导的应变可稳定数月，并使单层MoS2的局部带隙调谐达到约0.4 eV，为其本征带隙的约25%。 这代表了在二维单层材料中同时实现高幅度、空间分辨和持续应变的显著展示。 我们进一步将该方法扩展到双层WS2-MoS2异质结构。 这种应变工程技术为二维半导体中应变增强的控制开辟了一个新领域，以支持开发具有设计电子景观的宽谱光电设备和纳米电子器件。 显示英文摘要

Crystalline two-dimensional (2D) semiconductors often combine high elasticity and in-plane strength, making them ideal for strain-induced tuning of electronic characteristics, akin to strategies used in silicon electronics. However, current techniques fall short in achieving high-magnitude (>1%), spatially resolved, and stable strain in these materials. Here, we apply biaxial tensile strain up to 2.2%, with +/-0.12% resolution over micrometre-scale regions in monolayer MoS2 via conformal transfer onto patterned substrates fabricated using two-photon lithography. The induced strain is stable for months and enables local band gap tuning of ~0.4 eV in monolayer MoS2, ~25% of its intrinsic band gap. This represents a distinct demonstration of simultaneous high-magnitude, spatially resolved, and sustained strain in 2D monolayers. We further extend the approach to bilayer WS2-MoS2 heterostructures. This strain-engineering technique opens a new regime of strain-enabled control in 2D semiconductors to support the development of wide-spectrum optoelectronic devices and nanoelectronics with engineered electronic landscapes.

[2] arXiv:2508.01020 [中文pdf, pdf, html, 其他]

标题： 使用Pheasy代码的第一性原理声子物理 显示英文标题

标题： First-principles phonon physics using the Pheasy code

Changpeng Lin, Jian Han, Ben Xu, Nicola Marzari

评论： 19页正文和3幅图；29页附录材料

主题： 材料科学 (cond-mat.mtrl-sci)

从第一性原理出发的无参数晶格动力学计算在过去几十年中取得了显著进展，并在材料的热力学、相变和输运性质等方面得到了广泛应用。 当前的方法在推导晶格势能的原子间力常数（IFCs）时，当超越三阶非简谐性时变得具有挑战性，甚至有时不可行，这是由于高阶IFCs的数量出现组合爆炸。 在本工作中，我们提出了一种稳健且用户友好的程序Pheasy，它通过任意高阶的泰勒展开精确重建晶体固体的势能面。 给定力-位移数据集，该程序利用先进的机器学习算法高效且准确地提取IFCs，并进一步计算广泛范围的简谐和非简谐声子相关性质。 我们在三个典型示例中展示了获得的IFCs如何成功应用于研究非简谐晶格动力学和热输运。 通过这些详细的基准测试，我们也确定了IFCs提取的最佳方法，并为高保真晶格动力学模拟提供了通用指南，解决了从现有各种方案中提取的IFCs中的大不确定性。 总体而言，Pheasy项目旨在创建一个连接多种声子模拟平台的声子代码生态系统，并向广大研究社区提供访问权限。 显示英文摘要

Parameter-free calculations of lattice dynamics from first principles have achieved significant progress in the past decades, with a wealth of applications in thermodynamics, phase transitions, and transport properties of materials. Current approaches to derive the interatomic force constants (IFCs) of lattice potential become challenging and sometimes infeasible when going beyond third-order anharmonicity, due to the combinatorial explosion in the number of higher-order IFCs. In this work, we present a robust and user-friendly program, Pheasy, which accurately reconstructs the potential energy surface of crystalline solids via a Taylor expansion of arbitrarily high order. Given force-displacement datasets, the program enables an efficient and accurate extraction of IFCs using advanced machine-learning algorithms, and further calculates a wide range of harmonic and anharmonic phonon related properties. We show in three prototypical examples how the obtained IFCs have been successfully applied to study anharmonic lattice dynamics and thermal transport. Through these detailed benchmarks, we have also identified the optimal approach for IFC extractions and offered general guidelines for high-fidelity lattice-dynamical simulations, addressing the large uncertainties in the IFCs extracted from existing various schemes. Overall, the Pheasy project aims to create a phonon code ecosystem that connects diverse phonon simulation platforms and offers access to the broad research community.

[3] arXiv:2508.01028 [中文pdf, pdf, html, 其他]

标题： CALPHAD模型的构建与调优：使用机器学习原子间势和实验数据——Pt-W系统的案例研究 显示英文标题

标题： Construction and Tuning of CALPHAD Models Using Machine-Learned Interatomic Potentials and Experimental Data: A Case Study of the Pt-W System

Courtney Kunselman, Siya Zhu, Doguhan Sariturk, Raymundo Arroyave

主题： 材料科学 (cond-mat.mtrl-sci)

这项工作介绍了PhaseForgePlus——一种计算效率高、完全开源的工作流程，用于物理信息引导的CALPHAD模型生成和参数拟合。 以Pt-W系统为例，我们表明将机器学习势能整合到合金理论自动化工具包中，可以生成基于物理的吉布斯能描述，只需进行微小调整即可生成准确的相图。 在实验观察的背景下使用Jansson导数方法，这些调整可以通过梯度指导的优化过程高效且稳健地确定。 显示英文摘要

This work introduces PhaseForgePlus -- a computationally efficient, fully open-source workflow for physically-informed CALPHAD model generation and parameter fitting. Using the Pt-W system as an example, we show that the integration of Machine Learning Potentials into the Alloy Theoretic Automated Toolkit can produce physically grounded Gibbs energy descriptions requiring only slight adjustments to produce accurate phase diagrams. Employing the Jansson derivative method in the context of experimental observations, such adjustments can be efficiently and robustly determined through gradient-informed optimization procedures.

[4] arXiv:2508.01035 [中文pdf, pdf, html, 其他]

标题： 优化$α''$-Fe$_{16}$N$_2$作为永磁体的合金化 显示英文标题

标题： Optimizing $α''$-Fe$_{16}$N$_2$ as permanent magnet via alloying

Bo Zhao, Ruiwen Xie, Imants Dirba, Lambert Alff, Oliver Gutfleisch, Hongbin Zhang

主题： 材料科学 (cond-mat.mtrl-sci)

基于系统的第一性原理计算，我们研究了27种合金元素对Fe$_{16}$N$_2$内在磁性性质的影响，以进一步优化其用于永磁应用的性能。 基于形成能和到凸包的距离的热力学稳定性分析表明，20种元素可以替代Fe$_{16}$N$_2$，其中在掺杂时没有明显的位点偏好。 观察到所有合金元素基本上都能降低饱和磁化强度，而磁各向异性则可以显著改变。 就玻尔兹曼平均内在性质而言，我们识别出8种有趣的候选元素，其中Co、Mo和W是最有前景的进一步实验验证的案例。 显示英文摘要

Based on systematic first-principles calculations, we investigate the effects of 27 alloying elements on the intrinsic magnetic properties of Fe$_{16}$N$_2$, in order to further optimize its properties for permanent magnet applications. Analysis on the thermodynamic stabilities based on formation energy and distance to the convex hull reveals that 20 elements can be substituted into Fe$_{16}$N$_2$, where there is no strong site-preference upon doping. It is observed that all alloying elements can essentially reduce the saturation magnetization, whereas the magnetic anisotropy can be significantly modified. In terms of the Boltzmann-average intrinsic properties, we identify 8 elements as interesting candidates, with Co, Mo, and W as the most promising cases for further experimental validations.

[5] arXiv:2508.01177 [中文pdf, pdf, html, 其他]

标题： 一种晶体学度量用于连续量化晶胞变形 显示英文标题

标题： A Crystallographic Metric for Continuous Quantification of Unit Cell Deformation

Shannon Bernier, Gregory Bassen, Matthew Brem, Davor Tolj, Quentin Simmons, Tyrel M. McQueen

评论： 33页，包括附录，14幅图，已提交至《应用晶体学杂志》

主题： 材料科学 (cond-mat.mtrl-sci)

描述实际结构与假设的高对称性理想结构之间的偏差，可以成为理解和解释相变的强大工具。 这里我们引入了一个简单而有效的度量标准，用于量化相对于立方体的晶胞畸变程度，称为立方偏差度量标准。 这使得不同几何形状的晶胞之间能够进行连续比较。 我们通过四个独立的案例研究应用来展示该工具的潜力：1) 假蓝晶石中的不连续结构相变；2) 同源结构分类；3) 六方材料中的结构相关压电性；以及4) 铜氧化物家族中的超导材料设计。 尽管此度量标准并不能替代详细的结构或群论分析，但它能够在存在无序或缺乏群-子群关联的情况下，对不同成分和结构的化合物变体进行比较。 显示英文摘要

Describing the deviation of a real structure from a hypothetical higher-symmetry ideal can be a powerful tool to understand and interpret phase transitions. Here we introduce a simple yet effective metric that quantifies the degree of unit cell distortion relative to a cube, called the cubic deviation metric. This enables continuous comparisons between unit cells of different geometries. We demonstrate the potential of this tool with four separate case study applications to real material systems: 1) discontinuous structural phase transitions in pseudobrookites; 2) homological structure classification; 3) structure-correlated piezoelectricity in hexagonal materials; and 4) superconducting materials design in the cuprate family. Although this metric does not replace detailed structural or group theory analysis, it enables comparison across different compositional and structural compound variants, even in the presence of disorder or absence of group-subgroup correlation.

[6] arXiv:2508.01214 [中文pdf, pdf, html, 其他]

标题： $MoSe_2/V_2O_5$异质结构界面的磁性 显示英文标题

标题： Magnetism at the interface of $MoSe_2/V_2O_5$ heterostructures

Rohin Sharma, Diem Thi-Xuan Dang, Lilia M. Woods

主题： 材料科学 (cond-mat.mtrl-sci)

掺杂的过渡金属二硫属化物单层和范德华层间材料中的磁性引发了在纳米尺度上寻找可持续磁态的研究，旨在为自旋电子学应用构建器件。 在本研究中，我们报告了一种由$MoSe_2$过渡金属二硫属化物单层和$V_2O_5$基底组成的异质结构中磁性的存在。 通过密度泛函理论模拟，我们发现即使单独组分是非磁性的，$MoSe_2/V_2O_5$异质结构中也可以发现铁磁序。 通过检查该系统的电子结构和磁性，我们发现如果过渡金属二硫属化物或$V_2O_5$基底能够容纳点缺陷，出现的铁磁性会如何演变。 我们的研究表明，电荷转移与自旋重组之间的平衡可能导致新型混合材料中的界面磁性。 显示英文摘要

Magnetism in doped transition metal dichalcogenide monolayers and van der Waals interfaced materials have motivated the search for sustainable magnetic states at the nanoscale with the prospect of building devices for spintronics applications. In this study, we report the existence of magnetism in a heterostructure made up of an $MoSe_2$ transition metal dichalcogenide monolayer and a $V_2O_5$ substrate. Using density functional theory simulations, we find that ferromagnetic ordering can be found in the $MoSe_2/V_2O_5$ heterostructure even though the individual components are nonmagnetic. By examining the electronic structure and magnetic properties of this system we find how the occurring ferromagnetism evolves if the transition metal dichalcogenide or the $V_2O_5$ substrate can host point defects. Our study suggests that the balance between charge transfer and spin reorganization can lead to interface magnetism in novel hybrid materials.

[7] arXiv:2508.01289 [中文pdf, pdf, 其他]

标题： rutile GeO2 薄膜的光学性质研究 显示英文标题

标题： Study of Optical Properties of MOCVD-Grown Rutile GeO2 Films

Imteaz Rahaman, Anthony Bolda, Botong Li, Hunter D. Ellis, Kai Fu

评论： 18页，5图

主题： 材料科学 (cond-mat.mtrl-sci)

Rutile germanium dioxide (r-GeO$_2$) is a promising ultra-wide bandgap (UWBG) semiconductor, offering a high theoretical Baliga figure of merit, potential for p-type doping, and favorable thermal and electrical properties. In this work, we present a comprehensive optical investigation of crystalline r-GeO$_2$ thin films grown on r-TiO$_2$ (001) substrates via metal-organic chemical vapor deposition (MOCVD). Cathodoluminescence (CL) spectroscopy reveals broad visible emissions with distinct peaks near 470~nm and 520~nm. CL mapping indicates enhanced emission intensity in regions with larger crystalline domains, highlighting the correlation between domain size and optical quality. X-ray photoelectron spectroscopy (XPS) confirms the presence of Ge$^{4+}$ oxidation state and provides a bandgap estimation of $\sim$4.75~eV based on valence band and secondary electron cutoff analysis. UV--Vis transmittance measurements show a sharp absorption edge near 250--260~nm, corresponding to an optical bandgap in the range of 4.81--5.0~eV. These findings offer valuable insights into the defect-related emission behavior and band-edge characteristics of r-GeO$_2$, reinforcing its potential for future applications in power electronics and deep-ultraviolet optoelectronic devices. 显示英文摘要

Rutile germanium dioxide (r-GeO$_2$) is a promising ultra-wide bandgap (UWBG) semiconductor, offering a high theoretical Baliga figure of merit, potential for p-type doping, and favorable thermal and electrical properties. In this work, we present a comprehensive optical investigation of crystalline r-GeO$_2$ thin films grown on r-TiO$_2$ (001) substrates via metal-organic chemical vapor deposition (MOCVD). Cathodoluminescence (CL) spectroscopy reveals broad visible emissions with distinct peaks near 470~nm and 520~nm. CL mapping indicates enhanced emission intensity in regions with larger crystalline domains, highlighting the correlation between domain size and optical quality. X-ray photoelectron spectroscopy (XPS) confirms the presence of Ge$^{4+}$ oxidation state and provides a bandgap estimation of $\sim$4.75~eV based on valence band and secondary electron cutoff analysis. UV--Vis transmittance measurements show a sharp absorption edge near 250--260~nm, corresponding to an optical bandgap in the range of 4.81--5.0~eV. These findings offer valuable insights into the defect-related emission behavior and band-edge characteristics of r-GeO$_2$, reinforcing its potential for future applications in power electronics and deep-ultraviolet optoelectronic devices.

[8] arXiv:2508.01484 [中文pdf, pdf, 其他]

标题： 溅射沉积的Ni(V)/Al多层膜中无序晶体前混的实验证据 显示英文标题

标题： Experimental evidence of disordered crystalline premixing in sputter-deposited Ni(V)/Al multilayers

Michael J Abere, Paul G. Kotula, Jonathan S. Paras, David P. Adams

主题： 材料科学 (cond-mat.mtrl-sci)

溅射沉积交替层的Ni(V)和Al形成一种反应性多层结构，已知在点燃时会发生自传播形成反应。 顺序沉积过程导致每个包含的界面处反应物的纳米级预混合，最终影响多层放热性。 本工作通过扫描透射电子显微镜直接测量了Ni(V)/Al多层结构界面处的无序面心立方（FCC）固溶体预混相。 观察到的相的结晶度不同于之前报道的非晶中间层的先验预测。 无序的FCC相在135 C下退火16小时后仍保持其对称性，但晶格参数的变化与富铝成分一致。 Ni(V)/Al中晶体预混物的存在归因于结晶熵的电子贡献。 显示英文摘要

The sputter deposition of alternating layers of Ni(V) and Al forms a reactive multilayer known to undergo self-propagating formation reactions when ignited. The sequential deposition process leads to nm-scale premixing of reactants at each included interface which ultimately affects multilayer exothermicity. This work performs the direct measurement of a disordered face-centered cubic (FCC) solid solution premixed phase at the interfaces of Ni(V)/Al multilayers via scanning transmission electron microscopy. The crystallinity of the observed phase differs from previously reported a priori predictions of an amorphous interlayer. The disordered FCC phase retains its symmetry after annealing for 16 h at 135 C, but the lattice parameter shifts consistent with an Al-rich composition. The existence of a crystalline premix in Ni(V)/Al is attributed to the electronic contribution to the entropy of crystallization.

[9] arXiv:2508.01512 [中文pdf, pdf, html, 其他]

标题： 局部界面效应调制1T-TaS$_2$/1H-WSe$_2$异质结构的全局电荷秩序和光学性质 显示英文标题

标题： Local interface effects modulate global charge order and optical properties of 1T-TaS$_2$/1H-WSe$_2$ heterostructures

Samra Husremović, Valerie S. McGraw, Medha Dandu, Lilia S. Xie, Sae Hee Ryu, Oscar Gonzalez, Shannon S. Fender, Madeline Van Winkle, Karen C. Bustillo, Takashi Taniguchi, Kenji Watanabe, Chris Jozwiak, Aaron Bostwick, Eli Rotenberg, Archana Raja, Katherine Inzani, D. Kwabena Bediako

主题： 材料科学 (cond-mat.mtrl-sci)

1T-TaS$_2$是一种层状电荷密度波（CDW）晶体，表现出尖锐的相变和相关的电阻变化。 这些电阻台阶可以用于信息存储，这凸显了控制和调节CDW状态的重要性。 鉴于在 1T-TaS$_2$中面外相互作用的重要性，通过异质结构调制层间相互作用是一种调节CDW相变的有前途的方法。 在本工作中，我们研究了由 1T-TaS$_2$和单层 1H-WSe$_2$组成的异质结构的光学和电子性质。 通过系统地改变 1T-TaS$_2$的厚度及其与 1H-WSe$_2$的方位对齐，我们发现本征莫尔应变和界面电荷转移在 1T-TaS$_2$中引入了CDW无序，并改变了CDW有序温度。 此外，我们的研究显示，层间对齐影响1H-WSe$_2$中的激子动力学，表明异质结构可以同时调节1T-TaS$_2$的电子相和1H-WSe$_2$的光学性质。 这项工作提出了一种有前景的方法，用于工程化集成CDW材料和半导体的异质结构的光电行为。 显示英文摘要

1T-TaS$_2$ is a layered charge density wave (CDW) crystal exhibiting sharp phase transitions and associated resistance changes. These resistance steps could be exploited for information storage, underscoring the importance of controlling and tuning CDW states. Given the importance of out-of-plane interactions in 1T-TaS$_2$, modulating interlayer interactions by heterostructuring is a promising method for tailoring CDW phase transitions. In this work, we investigate the optical and electronic properties of heterostructures comprising 1T-TaS$_2$ and monolayer 1H-WSe$_2$. By systematically varying the thickness of 1T-TaS$_2$ and its azimuthal alignment with 1H-WSe$_2$, we find that intrinsic moir\'e strain and interfacial charge transfer introduce CDW disorder in 1T-TaS$_2$ and modify the CDW ordering temperature. Furthermore, our studies reveal that the interlayer alignment impacts the exciton dynamics in 1H-WSe$_2$, indicating that heterostructuring can concurrently tailor the electronic phases in 1T-TaS$_2$ and the optical properties of 1H-WSe$_2$. This work presents a promising approach for engineering optoelectronic behavior of heterostructures that integrate CDW materials and semiconductors.

[10] arXiv:2508.01624 [中文pdf, pdf, html, 其他]

标题： 热传输以及氢吸附对Linde类型A沸石咪唑酯框架的影响 显示英文标题

标题： Thermal transport and the impact of hydrogen adsorption in Linde Type A zeolitic imidazolate frameworks

Hyunseok Oh, Taeyong Kim

主题： 材料科学 (cond-mat.mtrl-sci)

热传导在金属有机框架（MOFs）中在多种应用中具有实际意义，例如气体储存和分离，因为不足的热量散发可能导致有害的影响。 尽管已有研究，但由于对控制热传导机制的理解不足，分子渗透对热传导的影响在许多MOFs中仍不明确。 在此，我们报告了沸石咪唑酯框架（ZIFs）中热传导特性的分子动力学研究。 我们研究了具有异常低热导率且温度依赖性趋势偏离许多晶体材料的Linde Type A拓扑ZIFs（ZIF-lta），尽管它们具有长程晶体秩序。 我们证明，热主要由平均自由路径与其波长相当的声子携带，类似于非晶固体中的扩散子，这是由于由包含大量金属中心的单元胞复杂性引起的强非谐性。 我们进一步表明，吸附的氢分子通过气体-气体或气体-框架相互作用增加了ZIFs的热导率，主要贡献是额外的振动模式。 我们的工作加深了对MOFs中热传导的基本理解，并提出了一种通过气体渗透来设计热传导的方法。 显示英文摘要

Thermal transport in metal-organic frameworks (MOFs) is of practical interest in diverse applications such as gas storage and separations, since insufficient heat dissipation can lead to detrimental effects. Despite investigations, influence of molecular infiltration on the heat transport remains unclear in many of MOFs due to poor understanding of mechanisms governing heat conductions. Here, we report molecular dynamics investigations of thermal transport properties in zeolitic imidazolate frameworks (ZIFs). We investigated Linde Type A topological ZIFs (ZIF-lta) exhibiting exceptionally low thermal conductivity with unusual trend of temperature dependence deviating from many crystalline materials, despite long-range crystalline order in them. We demonstrate that heat is predominantly carried by phonons with mean free paths comparable to their wavelengths, analogous to diffusons in amorphous solids owing to strong anharmonicity caused by complexity of unit cell consisting of a large number of metal centers. We further show that adsorbed hydrogen molecules increase thermal conductivity of ZIFs, mainly contributed by additional vibrational modes, as a result of gas-gas or gas-framework interactions. Our work advances fundamental understanding into the thermal transport in MOFs and suggests a means to engineer heat conduction via gas infiltrations.

[11] arXiv:2508.01688 [中文pdf, pdf, 其他]

标题： 一种非局部取向场相场模型用于各向异性和倾斜度依赖的晶界 显示英文标题

标题： A Non-Local Orientation Field Phase-Field Model for Misorientation- and Inclination- Dependent Grain Boundaries

Xiao Han, Axel van de Walle

主题： 材料科学 (cond-mat.mtrl-sci) ; 计算物理 (physics.comp-ph)

我们提出通过将晶界(GB)各向异性纳入相场建模，通过扩展标准偏微分方程公式，以包含方向场的非局部泛函。 无论模拟中的晶粒数量如何，该模型使用一个方向场，并利用在晶界附近的优化位置采样方向场获得的晶粒取向偏差和倾斜信息。 该形式化方法实现了GB能量各向异性的简单和精确调整，同时避免了广泛的拟合过程。 该泛函包括一个显式的GB各向异性函数，以控制GB能量作为取向偏差和倾斜的函数。 该模型通过再现线性晶粒生长速率、具有不同取向偏差和各向异性系数的Wulff形状以及三重结点处的解析平衡二面角进行了验证。 多晶模拟展示了晶粒生长、合并、三重结点行为以及各向异性对晶粒形态的影响。 显示英文摘要

We propose to incorporate grain boundary (GB) anisotropy in phase-field modeling by extending the standard partial differential equations formulation to include a non-local functional of an orientation field. Regardless of the number of grains in the simulation, the model uses a single orientation field and incorporates grain misorientation and inclination information obtained from sampling the orientation field at optimized locations in the vicinity of the grain boundary. The formalism enables simple and precise tuning of GB energy anisotropy while avoiding an extensive fitting procedure. The functional includes an explicit GB anisotropy function to control the GB energy as a function of both misorientation and inclination. The model is validated by reproducing the linear grain growth rate, Wulff shapes with varying misorientations and anisotropic coefficients, and analytical equilibrium dihedral angles at triple junctions. Polycrystalline simulations demonstrate grain growth, coalescence, triple junction behavior, and the influence of anisotropy on grain morphology.

[12] arXiv:2508.01707 [中文pdf, pdf, 其他]

标题： 一种使用压电响应力显微镜可视化铁电 Hf0.5Zr0.5O2 器件正交相均匀性的新方法 显示英文标题

标题： A Novel Methodology of Visualizing Orthorhombic Phase Uniformity in Ferroelectric Hf0.5Zr0.5O2 Devices Using Piezoresponse Force Microscopy

Wei-Cheng Peng, Hsien-Yang Liu, Cheng-Yu Yu, Artur Useinov, Tian-Li Wu

评论： 6页，7图

主题： 材料科学 (cond-mat.mtrl-sci) ; 应用物理 (physics.app-ph)

铁电Hf0.5Zr0.5O2 (HZO) 薄膜由于其与CMOS兼容性和可扩展性，对于下一代存储器和逻辑器件具有前景。 正交相（O相）的空间均匀性对于优化剩余极化等铁电性能至关重要。 本工作引入了一种新颖的压电响应力显微镜（PFM）方法，用于对HZO薄膜（5 nm，9 nm和20 nm）中的O相均匀性进行二维映射，并通过区分极化O相区域与非极化四方/单斜（T/M）相来进一步量化O相分布。 我们的结果表明，9 nm的薄膜表现出最均匀的O相和最高的剩余极化。 这种基于PFM的方法无需复杂的设施即可实现全面的相表征，拓宽了相分析的访问途径，并推动了用于存储器和逻辑应用的铁电薄膜研究。 显示英文摘要

Ferroelectric Hf0.5Zr0.5O2 (HZO) thin films are promising for next-generation memory and logic devices due to their CMOS compatibility and scalability. The spatial uniformity of the orthorhombic (O) phase is crucial for optimizing ferroelectric properties like remnant polarization. This work introduces a novel piezoresponse force microscopy (PFM) approach for 2D mapping of O-phase uniformity in HZO films (5 nm, 9 nm, and 20 nm), further quantifing O-phase distribution by distinguishing polarized O-phase regions from non-polarized tetragonal/monoclinic (T/M) phases. Our results reveal that the 9 nm film exhibits the most uniform O-phase and highest remnant polarization. This PFM-based method enables comprehensive phase characterization without requiring complicated facilities, broadening access to phase analysis and advancing ferroelectric thin-film research for memory and logic applications.

[13] arXiv:2508.01734 [中文pdf, pdf, 其他]

标题： 光诱导低自旋到高自旋转变在[2x2] Fe(II)金属网格中：在PETRA III的P11束线使用二极管激光泵浦光晶体学 显示英文标题

标题： Photoinduced Low Spin to High Spin Transition in a [2x2] Fe(II) Metallogrid: Diode Laser-Pumped Photocrystallography at the P11 Beamline in PETRA III, DESY

Krishnayan Basuroy, Jose de Jesus Velazquez-Garcia, Sreeju Sreekantan Nair Lalithambika, Argha Barman, Torben Reuss, Guillaume Pompidor, Alexander Grebentsov, Önder Akçaalan, Simone Techert

主题： 材料科学 (cond-mat.mtrl-sci) ; 化学物理 (physics.chem-ph)

我们报告在PETRA III同步加速器的P11光束线中首次尝试使用静态光晶体学，在[2x2] Fe(II)金属网格复合物中观察到从2HS-2LS状态到3HS-1LS状态的光诱导自旋交叉（SCO）转变。 使用了一类3B二极管激光器在受控照射条件下诱导该转变。 通过照射后的单晶X射线衍射（SCXRD）测量实现了结构表征，揭示了平均Fe-N距离的显著变化，这与SCO行为一致。 我们的实验装置能够精确对准，以使用一类3B二极管激光器进行光激发，并配备紧凑的聚焦光学系统。 二极管头和聚焦光学系统的组合装置的最大尺寸不超过32厘米。 该装置展示了紧凑型二极管激光系统的优势，即使在基于同步加速器的泵浦-探测光晶体学实验中也能方便地用于各种分子晶体。 显示英文摘要

We report on the photoinduced spin crossover (SCO) transition from a 2HS-2LS to a 3HS-1LS state in a [2x2] Fe(II) metallogrid complex using molecular crystals with static photocrystallography at a first ever attempt in the beamline P11 of the PETRA III synchrotron, DESY. A class 3B diode laser was used to induce the transition under controlled irradiation conditions. Structural characterization was achieved through single-crystal X-ray diffraction (SCXRD) measurements post-irradiation, revealing significant changes in average Fe-N distances, consistent with SCO behavior. Our experimental setup enables precise alignment necessary for photo-excitation using a class 3B diode laser along with a compact focusing optics. The longest dimension of the combined setup of the diode head and the focusing optics is not more than 32cm. The setup showcasing the utility of a compact diode laser system which can even be conveniently used in synchrotron-based pump-probe photocrystallography experiments for a wide range of molecular crystals.

[14] arXiv:2508.01757 [中文pdf, pdf, html, 其他]

标题： 从头计算的绿松石盐聚合物的光学性质：与最近实验数据的比较 显示英文标题

标题： Optical properties of emeraldine salt polymers from ab initio calculations: comparison with recent experimental data

Renato Colle, Pietro Parruccini, Andrea Benassi, Carlo Cavazzoni

期刊参考： J.物理化学。B 111 (2007) 2800-2805

主题： 材料科学 (cond-mat.mtrl-sci)

我们给出了用于其晶体三维极化子结构的绿松石盐导电聚合物的吸收系数{\alpha }({\omega })、横向介电函数{\epsilon }({\omega })、光学电导率{\sigma }({\omega }) 和反射率 R({\omega })。 我们利用Kohn-Sham DFT电子波函数和能量，在不考虑电子-空穴相互作用的带理论框架下，以宏观横向介电函数的形式表达。 通过向从头计算得到的介电函数中添加一个类似Drude项，考虑了带内跃迁的贡献。 与最近在高质量绿松石盐上测量的光学性质（Nature 441(2006)65-68）以及与其他绿松石盐记录的光学吸收光谱进行比较，结果非常令人满意。 计算得到的光谱是根据能带结构、态密度、带间和带内跃迁以及横向介电函数进行讨论的。 显示英文摘要

We present absorption coefficient {\alpha}({\omega}), transverse dielectric function {\epsilon}({\omega}), optical conductivity {\sigma}({\omega}), and reflectance R({\omega}) calculated for an emeraldine salt conducting polymer in its crystalline three-dimensional polaronic structure. We utilize Kohn-Sham DFT electronic wavefunctions and energies implemented in the expression of the macroscopic transverse dielectric function in the framework of the band theory without the electron-hole interaction. Contributions of intra-band transitions are taken into account by adding a Drude-like term to the dielectric function calculated ab-initio. Comparison with optical properties, recently measured on high-quality emeraldine salts (Nature 441(2006)65-68), and with optical absorption spectra, recorded on other emeraldine salts, is very satisfactory. The calculated spectra are discussed in terms of energy-band structure, density of states, inter- and intra-band transitions and transverse dielectric function.

[15] arXiv:2508.01822 [中文pdf, pdf, html, 其他]

标题： 基于深度学习的潜在空间插值微结构演化预测 显示英文标题

标题： Deep Learning-Driven Prediction of Microstructure Evolution via Latent Space Interpolation

Sachin Gaikwad, Thejas Kasilingam, Owais Ahmad, Rajdip Mukherjee, Somnath Bhowmick

评论： 7个数字

主题： 材料科学 (cond-mat.mtrl-sci) ; 人工智能 (cs.AI)

相场模型能够准确模拟微观结构演化，但其依赖于求解复杂的微分方程，导致计算成本高昂。 本研究通过一种新的基于深度学习的框架实现了显著加速，该框架结合了条件变分自编码器（CVAE）与三次样条插值和球面线性插值（SLERP）。 我们通过从有限的一组训练成分预测中间合金成分的微观结构演化来展示该方法在二元spinodal分解中的应用。 首先，利用二元spinodal分解的相场模拟得到的微观结构，我们训练CVAE，该模型学习到能够编码关键形态特征的紧凑潜在表示。 接下来，我们在潜在空间中使用三次样条插值来预测任何未知成分的微观结构。 最后，SLERP确保随时间推移的形态演化平滑，并且与粗化过程非常相似。 预测的微观结构在视觉和统计上与相场模拟具有高度相似性。 该框架为微观结构演化提供了一个可扩展且高效的代理模型，能够加速材料设计和成分优化。 显示英文摘要

Phase-field models accurately simulate microstructure evolution, but their dependence on solving complex differential equations makes them computationally expensive. This work achieves a significant acceleration via a novel deep learning-based framework, utilizing a Conditional Variational Autoencoder (CVAE) coupled with Cubic Spline Interpolation and Spherical Linear Interpolation (SLERP). We demonstrate the method for binary spinodal decomposition by predicting microstructure evolution for intermediate alloy compositions from a limited set of training compositions. First, using microstructures from phase-field simulations of binary spinodal decomposition, we train the CVAE, which learns compact latent representations that encode essential morphological features. Next, we use cubic spline interpolation in the latent space to predict microstructures for any unknown composition. Finally, SLERP ensures smooth morphological evolution with time that closely resembles coarsening. The predicted microstructures exhibit high visual and statistical similarity to phase-field simulations. This framework offers a scalable and efficient surrogate model for microstructure evolution, enabling accelerated materials design and composition optimization.

[16] arXiv:2508.01826 [中文pdf, pdf, html, 其他]

标题： Weyl半金属Co$_3$Sn$_2$S$_2$表面化学和电子景观的中尺度变化通过ARPES和XPS可视化 显示英文标题

标题： Mesoscale variations of chemical and electronic landscape on the surface of Weyl semimetal Co$_3$Sn$_2$S$_2$ visualized by ARPES and XPS

Sudheer Anand Sreedhar, Matthew Staab, Mingkun Chen, Robert Prater, Zihao Shen, Giuseppina Conti, Ittai Sidilkover, Zhenghong Wu, Eli Rotenberg, Aaron Bostwick, Chris Jozwiak, Hadas Soifer, Slavomir Nemsak, Sergey Y. Savrasov, Vsevolod Ivanov, Valentin Taufour, Inna M. Vishik

主题： 材料科学 (cond-mat.mtrl-sci) ; 中尺度与纳米尺度物理 (cond-mat.mes-hall) ; 强关联电子 (cond-mat.str-el)

磁性外尔半金属Co$_3$Sn$_2$S$_2$中的多重晶体终止显示了不同的拓扑和平凡表面态，这些已经成功地在实验中被区分。然而，已知纯终止模型是不充分的，因为这些表面表现出高度的空间异质性和点缺陷。在这里，我们使用光电子测量结合核心能级的第一性原理计算，对表面化学和表面电子结构进行了谱显微研究。我们识别出一个中间区域，其特性与硫终止和锡终止都不同，并证明该区域的光谱特征可以与具有不同表面锡空位密度的无序锡终止相关联。最后，我们展示了如何结合算法和机器学习分析光电子数据，以提取识别特征，分类空间区域，并将局部化学与局部电子结构相关联。 显示英文摘要

The multiple crystalline terminations in magnetic Weyl semimetal Co$_3$Sn$_2$S$_2$ display distinct topological and trivial surface states, which have successfully been distinguished experimentally. However, a model of pure terminations is known to be inadequate because these surfaces exhibit a high degree of spatial heterogeneity and point disorder. Here we perform a spectromicroscopy study of the surface chemistry and surface electronic structure using photoemission measurements in combination with first-principles calculations of core levels. We identify an intermediate region with properties distinct from both the sulfur and tin terminations, and demonstrate that the spectral features in this region can be associated with a disordered tin termination with a varying density of surface tin-vacancies. Finally, we show how a combination of algorithmic and machine learning analysis of photoemission data can be used to extract identifying features, classify spatial regions, and correlate local chemistry with local electronic structure.

[17] arXiv:2508.01838 [中文pdf, pdf, 其他]

标题： 基于MnSb(1-101)的自旋电子器件的聚焦离子束光刻 patterning 显示英文标题

标题： Focused Ion Beam patterning of MnSb(1-101) based spintronic devcies

Stuart N. Holmes, Jonathan Gough, Ethan Dommett, Gavin R. Bell

评论： 18页，7图，27参考文献

主题： 材料科学 (cond-mat.mtrl-sci) ; 中尺度与纳米尺度物理 (cond-mat.mes-hall)

低温输运测量结果展示的是使用30 keV的镓聚焦离子束FIB系统对铁磁性MnSb器件的磁性特性进行图案化后的结果。 FIB图案化引入了无序，本文通过纵向电阻率和霍尔电导的反常霍尔效应贡献的测量来量化这种无序。 MnSb的结构相是镍矿相，并且除了体态之外还有表面态。 FIB剂量高达每平方厘米1E16个镓离子会降低各向异性磁阻信号，但在垂直磁场B中会增加反常霍尔效应信号的大小。 在未受损的器件中，霍尔电导的反常霍尔效应贡献为e平方除以h，其中e是电子电荷，h是普朗克常数。 该量对由镓离子束引起的无序程度敏感，在剂量水平超过每平方厘米1E16个镓离子时会降至零。 在磁化饱和后，电阻率表现出对B的对数依赖性，低场各向异性磁阻贡献为0.12%。 在对数B行为的磁场范围内，电导变化为e平方除以h。 在高FIB剂量水平下，电阻率对对数B依赖性的拟合有所降低，并且取决于损伤的均匀性。 在MnSb中图案化纳米结构磁行为，并与反铁磁材料兼容，特别是CrSb的镍矿相以及传输中的非平凡贝里相贡献，使得这种铁磁材料和图案化技术对未来自旋电子器件的发展具有重要意义。 显示英文摘要

Low temperature transport measurements are presented of ferromagnetic MnSb devices with the magnetic properties patterned using a Ga focused ion beam FIB system at 30 keV. FIB patterning introduces disorder and this is quantified in this paper through measurements of the longitudinal resistivity and the anomalous Hall effect contribution to the Hall conductivity. The MnSb structural phase is the niccolite phase with a surface state in addition to bulk states. FIB doses up to 1E16 Ga ions per square cm reduces the anisotropic magnetoresistance signal but increases the size of the anomalous Hall effect signal in out of plane magnetic fields, B. The anomalous Hall effect contribution to the Hall conductivity is e squared divided by h in the undamaged devices, where e is the electronic charge and h is Plancks constant. This quantity is sensitive to the level of disorder induced by the Ga ion beam, reducing to zero at dose levels greater than 1E16 Ga ions per square cm. The resistivity shows a logarithmic B dependence after the magnetization has saturated with the low field anisotropic magnetoresistance contribution of 0.12 percent. The conductivity change is e squared divided by h in the magnetic field range of logarithmic B behavior. The resistivity shows a reduced fit to a logarithmic B dependence at high FIB dose levels and is dependent on the damage uniformity. Patterning nanostructured magnetic behavior in MnSb, with compatibility to altermagnetic materials, in particular the niccolite phase of CrSb and non trivial Berry phase contributions to transport make this ferromagnetic material and patterning technique useful for future spintronic device development.

[18] arXiv:2508.02101 [中文pdf, pdf, 其他]

标题： 降低CPP-GMR器件中自旋转移矩诱导磁化翻转的临界电流：$Co_2FeGa_{0.5}Ge_{0.5}$Heusler合金中低阻尼和增强的自旋散射不对称性的影响 显示英文标题

标题： Reducing critical current for spin-transfer-torque-induced magnetization reversal in CPP-GMR devices: effect of low damping and enhanced spin scattering asymmetry in $Co_2FeGa_{0.5}Ge_{0.5}$ Heusler alloy

Vineet Barwal, Hirofumi Suto, Yuya Sakuraba

主题： 材料科学 (cond-mat.mtrl-sci)

自旋转移矩（STT）在磁阻器件中的应用，已实现了诸如STT-磁阻随机存取存储器、自旋转移振荡器和能量辅助磁记录等关键应用。 在器件结构中，自由层（FL）的磁化方向通过来自自旋注入层（SIL）的自旋注入进行操控，操作所需的临界电流密度与FL的阻尼（$\alpha$）常数成正比，并与STT效率成反比，而STT效率取决于材料的自旋极化（$P$）。 在此，我们研究了低 $\alpha$ 和高 $P$ 的 $Co_2FeGa_{0.5}Ge_{0.5}$（CFGG）Heusler合金对垂直于平面巨磁阻器件中STT引起的磁化翻转所需操作电流的影响。 与采用传统NiFe-FL的器件相比，采用CFGG作为FL材料的器件实现了操作电流的大幅降低，这是由于CFGG具有非常低的 $\alpha$，这证明了CFGG作为FL材料的优势。 鉴于CFGG在SIL中具有高自旋极化的优点，我们分析了由CoFe和薄CFGG层组成的双层SIL的影响，重点是利用CoFe/CFGG界面处的自旋散射不对称性。 采用CoFe/CFGG-SIL的器件表现出最低的临界电流，证明了STT效率的增强。 此外，全面研究了STT效率与磁阻比之间的相关性，结果表明，在CoFe/CFGG-SIL中，器件间的STT效率分布较小。 这些发现突显了CFGG Heusler合金和CoFe/CFGG双层结构在开发高效稳定STT基自旋电子器件中的潜在价值。 显示英文摘要

Spin-transfer torque (STT) in magnetoresistance devices has enabled key applications such as STT-magnetoresistive random access memory, spin torque oscillators, and energy-assisted magnetic recording. In the device structures, where a free layer (FL) magnetization is manipulated by spin injection from a spin injection layer (SIL), the critical current density required for operation is directly proportional to the damping ($\alpha$) constant of FL and inversely proportional to the STT efficiency, which depends on the spin polarization ($P$) of the materials. Here, we investigate the effect of low $\alpha$ and high $P$ of $Co_2FeGa_{0.5}Ge_{0.5}$(CFGG) Heusler alloy on the operation current required for STT-induced magnetization reversal in current perpendicular-to-plane giant magnetoresistance devices. Devices with CFGG as a FL material achieved a large reduction in the operation current, as compared to those with conventional NiFe-FL owing to the very low $\alpha$ of CFGG, demonstrating the advantage of CFGG as a FL material. As the advantage of high spin polarization CFGG for SIL, we analyzed the effect of bilayer SIL consisting of CoFe and thin CFGG layers, focusing on utilizing the spin scattering asymmetry at the CoFe/CFGG interface. Devices with the CoFe/CFGG-SIL exhibited the lowest critical current, demonstrating enhanced STT efficiency. In addition, the correlation of STT efficiency with magnetoresistance ratio were comprehensively investigated, showing that device-to-device distribution in STT-efficiency was smaller in CoFe/CFGG-SIL. These findings highlight the potential of CFGG Heusler alloy and CoFe/CFGG bilayer structures as key components for the development of efficient and stable STT-based spintronic devices.

[19] arXiv:2508.02142 [中文pdf, pdf, 其他]

标题： 柔性范德华半导体InSe的本征物理性质 显示英文标题

标题： Intrinsic physical properties of flexible van der Waals semiconductor InSe

Jacob Svane, Kim-Khuong Huynh, Yong P. Chen, Bo Brummerstedt Iversen

主题： 材料科学 (cond-mat.mtrl-sci)

InSe是一种范德华半导体，其具有机械柔韧性、高电子迁移率和非平凡的电子结构，使其成为进行有趣的基础研究和有前景的器件开发的有吸引力的平台。 然而，相纯的本征InSe晶体的成核和生长需要严格的热力学条件，因此一直难以实现。 由于InSe不一致熔化，基于1:1 In-Se混合物冷却的常用合成方法将产生多相晶粒的聚集体或不受控制的富In、高度电子掺杂的InSe。 这一基本的热力学限制为报道的InSe物理性质中观察到的巨大差异提供了有力的解释。 我们通过利用移动溶剂浮区（TSFZ）方法来生产高质量、厘米大小的InSe单晶，从而克服了这些限制。 电气、热和热电输运测量表明，TSFZ-InSe单晶非常接近本征极限，确立了它作为未来研究这种重要材料的基准材料。 显示英文摘要

InSe is a van der Waals semiconductor in which mechanical flexibility, high electronic mobility, and non-trivial electronic structures converge, making it an attractive platform for both intriguing fundamental studies and promising device developments. However, the nucleation and growth of phase-pure, intrinsic InSe crystals require stringent thermodynamical conditions, and have therefore remained elusive. Since InSe melts incongruently, the widely used synthesis methods based on cooling of a 1:1 In-Se mixture will produce either aggregates of multiphase crystallites or uncontrolled In-rich, heavily electron-doped InSe. This fundamental thermodynamic constraint provides a compelling explanation for the large discrepancies observed in the reported physical properties of InSe. We overcome these limitations by utilizing the traveling solvent floating zone (TSFZ) method to produce high quality, centimeter-size InSe single crystals. Electrical, thermal, and thermoelectric transport measurements demonstrate that TSFZ-InSe single crystals closely approach the intrinsic limit, establishing it as a benchmark material for the future studies of this important material.

[20] arXiv:2508.02163 [中文pdf, pdf, 其他]

标题： 新兴电光分子晶体用于光电集成 显示英文标题

标题： Emerging electro-optic molecular crystals for optoelectronic integration

Keishi Sunami, Sachio Horiuchi, Yoriko Sonoda, Naomi Fujiki, Toshiki Higashino, Yuki Atsumi, Shoji Ishibashi, Jun'ya Tsutsumi

评论： 21页，6图，2表，附加支持信息在文稿末尾

主题： 材料科学 (cond-mat.mtrl-sci) ; 光学 (physics.optics)

通信技术的快速发展需要开发混合光学调制器，将硅光子学与电光（EO）材料相结合，以实现超高速、低功耗和紧凑的光子器件。 然而，目前尚无任何材料能同时满足高EO性能、工艺兼容性和热稳定性的要求，而这些是实际光电集成所必需的。 在此，我们介绍了4-(4'-硝基苯偶氮)二苯胺（NDPA）及其衍生物，这些新型非线性光学分子晶体是通过结合晶体形态预测的材料筛选方法发现的。 它们通过熔体的毛细作用表现出结晶成高质量定向薄膜和超细硅槽填充的能力。 所得的EO性能远超传统铌酸锂，并与最先进的EO聚合物相当，在393 K下保持优异的热稳定性超过1000小时。目前满足上述所有要求的EO材料是硅-有机混合光学调制器的有前途的候选材料，为可扩展和高性能光电技术迈出了重要一步。 显示英文摘要

The rapid advancement of communication technology necessitates the development of hybrid optical modulators that integrate silicon photonics with electro-optic (EO) materials to enable ultrafast, low-power, and compact photonic devices. However, no existing material simultaneously meets the requirements for high EO performance, process compatibility, and thermal stability, which are essential for practical optoelectronic integration. Here, we present 4-(4'-nitrophenylazo)diphenylamine (NDPA) and its derivative, novel nonlinear optical molecular crystals discovered through materials screening incorporating crystal habit prediction. They demonstrate crystallization into high-quality aligned thin films and ultrafine silicon slot fillings through the capillary action of melts. The resulting EO performance much exceed that of conventional lithium niobate and are comparable to state-of-the-art EO polymers, with excellent thermal stability maintained for over 1000 hours at 393 K. The present EO materials satisfying all the requirements above are promising candidates for silicon-organic hybrid optical modulators, opening a significant step toward scalable and high-performance optoelectronic technologies.

[21] arXiv:2508.02251 [中文pdf, pdf, html, 其他]

标题： 铝的低对 continuum 中的取向效应 显示英文标题

标题： Orientational Effects in the Low Pair Continuum of Aluminium

Thomas Gawne, Zhandos A Moldabekov, Oliver S Humphries, Motoaki Nakatsutsumi, Sebastian Schwalbe, Jan Vorberger, Ulf Zastrau, Tobias Dornheim, Thomas R Preston

主题： 材料科学 (cond-mat.mtrl-sci) ; 等离子体物理 (physics.plasm-ph)

我们比较了环境多晶铝的动态结构因子（DSF）在对偶连续区内的时间依赖密度泛函理论（TDDFT）预测结果与最近在欧洲XFEL收集的超高分辨率X射线汤姆逊散射测量结果。 TDDFT在所研究的波数处预测了强烈的各向异性，即使考虑了$q$-模糊效应。 实验光谱具有足够的分辨率和信噪比来分辨这些取向依赖性，因此多晶样品的取向平均被严格观察到。 一旦考虑到取向平均，TDDFT就能够充分再现实验光谱。 最后，将从jellium预测的DSF与实验进行比较，证明了在建模多晶材料的光谱时考虑晶格效应的重要性。 显示英文摘要

We compare the predictions of the dynamic structure factor (DSF) of ambient polycrystalline aluminium from time-dependent density functional theory (TDDFT) in the pair continuum regime to recent ultrahigh resolution x-ray Thomson scattering measurements, collected at the European XFEL. TDDFT predicts strong anisotropy in the DSF at the wavenumber examined here, even with $q$-blurring accounted for. The experimental spectrum has more than sufficient resolution and signal-to-noise levels to resolve these orientation dependencies, and therefore the orientational averaging of the polycrystalline sample is observed rigorously. Once the orientation averaging is accounted for, TDDFT is able to reproduce the experimental spectrum adequately. Finally, comparisons of predicted DSFs from jellium to experiment demonstrates the importance of accounting for lattice effects in modelling the spectrum from a polycrystal.

[22] arXiv:2508.02388 [中文pdf, pdf, html, 其他]

标题： 无扭曲的腔量子电动力学控制的二维莫尔激子 显示英文标题

标题： Cavity-QED-controlled two-dimensional Moiré Excitons without twisting

Francesco Troisi, Hannes Hübener, Angel Rubio, Simone Latini

主题： 材料科学 (cond-mat.mtrl-sci) ; 量子物理 (quant-ph)

我们提出了一种全光莫尔-like 电子束缚，通过空间周期性光学腔实现。 这种周期性光子结构可以通过将物质激发与受限光子及其量子涨落耦合来控制材料特性。 我们开发了一种低能非微扰的量子电动力学描述，用于强耦合的激子和有限动量转移的光子。 我们发现，在激光驱动腔的经典极限下，产生的光学约束直接模拟了莫尔物理。 而在暗腔中，光的量子涨落的存在本身就会导致激子带和有效质量的显著重整化。 我们将这些效应归因于长程腔介导的激子-激子相互作用，这只能在非微扰处理中捕捉到。 基于这些发现，我们提出空间结构化的腔作为腔材料工程的一种有前途的途径。 显示英文摘要

We propose an all-optical Moir\'e-like exciton confinement by means of spatially periodic optical cavities. Such periodic photonic structures can control the material properties by coupling the matter excitations to the confined photons and their quantum fluctuations. We develop a low energy non-perturbative quantum electro-dynamical description of strongly coupled excitons and photons at finite momentum transfer. We find that in the classical limit of a laser driven cavity the induced optical confinement directly emulates Moir\'e physics. In a dark cavity instead, the sole presence of quantum fluctuations of light generates a sizable renormalization of the excitonic bands and effective mass. We attribute these effects to long-range cavity-mediated exciton-exciton interactions which can only be captured in a non-perturbative treatment. With these findings we propose spatially structured cavities as a promising avenue for cavity material engineering.

[23] arXiv:2508.02394 [中文pdf, pdf, html, 其他]

标题： 二硫化钼粘滑切割中的雪崩动力学 显示英文标题

标题： Avalanche Dynamics in Stick-Slip Cutting of Molybdenum Disulfide

Pawel Koczanowski, Paolo Nicolini, Hesam Khaksar, Enrico Gnecco

主题： 材料科学 (cond-mat.mtrl-sci)

我们通过在足以引发平面断裂的法向载荷下弹性驱动尖锐钻石探针，研究了多层MoS2上的纳米尺度磨损，这是旗舰过渡金属二硫化物。伴随的摩擦和由此产生的磨损结构首先通过原子力显微镜（AFM）进行表征，揭示了一个导致MoS2芯片逐步剥离的粘滑区域。在高法向力下，滑动阶段表现出雪崩动力学的标志性特征，这是首次在纳米尺度上观察到，由摩擦力下降的广义极值分布所证实。AFM表征得到了分子动力学模拟的验证，这些模拟再现了实验趋势，并揭示了磨损过程的原子细节，包括局部非晶化、层弯曲以及不同耗散通道的参与。值得注意的是，似乎只有五分之一输入系统的能量被用于不可逆地损坏MoS2表面。这些结果为层状固体中摩擦和磨损的物理机制提供了新的见解，并为范德华材料在亚微米尺度上的精密切割和纳米加工提供了框架，这对下一代器件具有重要意义。 显示英文摘要

We have investigated nanoscale wear on multilayered MoS2, the flagship transition metal dichalcogenide, by elastically driving sharp diamond tips under normal loads sufficient to induce in-plane fracture. The accompanying friction and the resulting wear structures were first characterized by atomic force microscopy (AFM), revealing a stick-slip regime that drives progressive exfoliation of MoS2 chips. At high normal forces, the slip phase displays hallmark signatures of avalanche dynamics, observed for the first time at the nanoscale, evidenced by a Generalized Extreme Value distribution of friction force drops. The AFM characterization is corroborated by molecular dynamics simulations, which reproduce experimental trends and uncover atomistic details of the wear process, including local amorphization, layer curving, and the involvement of distinct dissipative channels. Notably, it appears that only one-fifth of the energy inputted into the system is used to damage the MoS2 surface irreversibly. These results offer new insight into the physical mechanisms governing friction and wear in layered solids and provide a framework for precision cutting and nanomachining in van der Waals materials, relevant to next-generation devices at sub-micrometer scales.

[24] arXiv:2508.02415 [中文pdf, pdf, 其他]

标题： 外延Mn$_3$Sn(0001)非共线反铁磁薄膜中的高效自旋泵浦和自旋-电荷转换 显示英文标题

标题： Efficient spin-pumping and spin-to-charge conversion in epitaxial Mn$_3$Sn(0001) noncollinear antiferromagnetic films

Surya N. Panda, Ning Mao, Nikolai Peshcherenko, Xiaolong Feng, Yang Zhang, Anastasios Markou, Claudia Felser, Edouard Lesne

主题： 材料科学 (cond-mat.mtrl-sci)

自旋电流的生成和控制对于推进下一代自旋电子技术至关重要。 这些技术依赖于能够高效地产生和相互转换自旋和电荷电流的材料，同时克服与传统铁磁体和重金属相关的一些限制。 例如，Kagome拓扑反铁磁外尔半金属Mn$_3$Sn由于其独特的磁序和显著的贝里曲率驱动的输运现象，表现出独特的优势。 在本研究中，我们系统地研究了外延(0001)取向的Mn$_3$Sn薄膜中的自旋电流生成和自旋-电荷转换现象。 我们的研究结果揭示了室温下源自内在和外在贡献的自旋霍尔角度为0.9$\%$，以及近似各向同性的面内自旋霍尔电导率为44.4~($\hbar$/e) $\Omega^{-1}$.cm$^{-1}$，这在第一性原理计算的背景下进行了讨论。 此外，在Mn$_3$Sn(0001)/Ni$_{81}$Fe$_{19}$异质结构中，我们观察到高自旋混合电导率为28.52 nm$^{-2}$，以及界面自旋透明度约为72$\%$。 值得注意的是，我们还发现Mn$_3$Sn(0001)外延薄膜中的自旋扩散长度在室温下超过15 nm。 我们的结果突显了拓扑Weyl非共线反铁磁体Mn$_3$Sn在潜在自旋电子学应用中作为高效自旋传输和转换材料的潜力。 显示英文摘要

The generation and control of spin currents are crucial for advancing next-generation spintronic technologies. These technologies depend on materials capable of efficiently sourcing and interconverting spin and charge currents, while overcoming some limitations associated with conventional ferromagnets and heavy metals. Kagome topological antiferromagnetic Weyl semimetals, such as Mn$_3$Sn, present unique advantages owing to their distinct magnetic order and significant Berry curvature-driven transport phenomena. In this study, we systematically investigate spin current generation and spin-to-charge conversion phenomena in epitaxial (0001)-oriented Mn$_3$Sn thin films. Our findings reveal a spin Hall angle of 0.9$\%$ and a nearly isotropic in-plane spin Hall conductivity of 44.4~($\hbar$/e) $\Omega^{-1}$.cm$^{-1}$ at room temperature, originating from a combination of intrinsic and extrinsic contributions, as discussed in light of first-principle calculations. Furthermore, in Mn$_3$Sn(0001)/Ni$_{81}$Fe$_{19}$ heterostructures, we observe a high spin-mixing conductance of 28.52 nm$^{-2}$ and an interfacial spin-transparency of approximately 72$\%$. Notably, we also find that the spin diffusion length in Mn$_3$Sn(0001) epitaxial films exceeds 15 nm at room temperature. Our results highlight the potential of the topological Weyl noncollinear antiferromagnet Mn$_3$Sn as an efficient material for spin transport and conversion in prospective spintronic applications.

[25] arXiv:2508.02581 [中文pdf, pdf, 其他]

标题： 具有设计电子态的人工晶格结构的自动构建 显示英文标题

标题： Automated Construction of Artificial Lattice Structures with Designer Electronic States

Ganesh Narasimha, Mykola Telychko, Wooin Yang, Arthur P. Baddorf, P. Ganesh, An-Ping Li, Rama Vasudevan

主题： 材料科学 (cond-mat.mtrl-sci)

利用扫描隧道显微镜（STM）操控物质，能够创建出原子定义的人工结构，这些结构可以容纳设计的量子态。 然而，操控过程耗时较长，加上STM探针的敏感性，限制了对各种配置的探索，并限制了设计特征的大小。 在本研究中，我们提出了一种基于强化学习（RL）的框架，通过STM探针在铜基底上空间操控一氧化碳（CO）分子来创建人工结构。 自动化的工作流程结合了分子检测和操控，采用基于深度学习的目标检测来定位CO分子，并使用线性分配算法将这些分子分配到指定的目标位置。 我们首先基于随机参数采样进行分子操作，以减少样本偏差、隧道电流设定点和操控速度。 然后将此数据集结构化为用于训练RL代理的动作轨迹。 随后将模型部署在STM上，在结构构建过程中进行实时操控参数微调。 我们的方法结合路径规划协议和主动漂移补偿，以显著减少人工输入，实现原子级精确的结构制造，同时实现具有所需电子特性的更大规模人工晶格。 为了证明我们方法的效率，我们展示了扩展人工石墨烯晶格的自动构建，并确认其电子结构中存在特征狄拉克点。 还讨论了基于RL的结构组装可扩展性的进一步挑战。 显示英文摘要

Manipulating matter with a scanning tunneling microscope (STM) enables creation of atomically defined artificial structures that host designer quantum states. However, the time-consuming nature of the manipulation process, coupled with the sensitivity of the STM tip, constrains the exploration of diverse configurations and limits the size of designed features. In this study, we present a reinforcement learning (RL)-based framework for creating artificial structures by spatially manipulating carbon monoxide (CO) molecules on a copper substrate using the STM tip. The automated workflow combines molecule detection and manipulation, employing deep learning-based object detection to locate CO molecules and linear assignment algorithms to allocate these molecules to designated target sites. We initially perform molecule maneuvering based on randomized parameter sampling for sample bias, tunneling current setpoint and manipulation speed. This dataset is then structured into an action trajectory used to train an RL agent. The model is subsequently deployed on the STM for real-time fine-tuning of manipulation parameters during structure construction. Our approach incorporates path planning protocols coupled with active drift compensation to enable atomically precise fabrication of structures with significantly reduced human input while realizing larger-scale artificial lattices with desired electronic properties. To underpin of efficiency of our approach we demonstrate the automated construction of an extended artificial graphene lattice and confirm the existence of characteristic Dirac point in its electronic structure. Further challenges to RL-based structural assembly scalability are discussed.

[26] arXiv:2508.02598 [中文pdf, pdf, 其他]

标题： 铁电ε-WO3纳米颗粒及其在室温下的双极子驱动光电特性 显示英文标题

标题： Ferroelectric Epsilon-WO3 Nanoparticles and Its Bipolaron Driven Opto-electronic Properties at Room Temperature

Mohammad M. Rahaman, Jose Flores, Mohamed Y. Noor, Md Mohsinur R. Adnan, Alex Blackston, Enam Chowdhury, Roberto C. Myers, Michael Newburger, Pelagia-Irene Gouma

评论： 21页，4图

主题： 材料科学 (cond-mat.mtrl-sci) ; 应用物理 (physics.app-ph)

一种独特的二元三氧化钨的多形体，即WO3的ε相，具有非对称中心的铁电结构，在块体中通常在-43摄氏度以下稳定。我们通过火焰喷雾热解合成方法在室温（RT）和纳米结构粉末中稳定了ε-WO3。这些纳米粉末滴铸成均匀的薄膜，以实现室温下铁电和光电性能的测量。我们报告了通过压电响应力显微镜（PFM）测得的铁电滞后、纳米尺度畴和偶极子切换。ε-WO3薄膜还表现出光学二次谐波生成（SHG）和逆时针铁电蝴蝶形电容-电压滞后，进一步证明了ε-WO3的铁电性质。值得注意的是，ε-WO3在室温下对光刺激表现出铁电极化响应并形成双极子，这是一种此前仅在低温下发现的自旋为零的准粒子。双极子的形成及其与电光刺激的相互作用导致单层固态蓝色着色，这是一种铁致变色效应。讨论了铁致变色效应的机制。总之，ε-WO3似乎是一种结构最简单的铁电材料，在室温下形成玻色子自旋为零的双极子，并且其偶极子对光电信号有响应；因此，这种材料在光电领域具有重要的前景。 显示英文摘要

A unique polymorph of binary tungsten trioxide, the epsilon phase of WO3, has non-centrosymmetric ferroelectric structure, typically stable below -43 degree C in bulk. We have stabilized the epsilon-WO3 at room temperature (RT) and nanostructured powders via flame spray pyrolysis synthesis. These nanopowders are drop cast into uniform thin films to enable RT measurement of ferroelectric and optoelectronic properties. We report ferroelectric hysteresis, nanoscale domains, and dipole switching measured via Piezo-response force microscopy (PFM). The epsilon-WO3 films also display optical second harmonic generation (SHG) and anticlockwise ferroelectric butterfly capacitance versus voltage hysteresis, further demonstrating the ferroelectric nature of epsilon-WO3. Remarkably, epsilon-WO3 shows ferroelectric polarization responses to optical stimuli and form bipolaron at RT, a spin-zero quasiparticle previously found only in cryogenic temperatures. The bipolaron formation and its interaction with electro-optical stimuli results in a single layer solid-state blue coloration, a ferrochromic effect. A mechanism of the ferrochromic effect is discussed. In summary, epsilon-WO3 appears to be a ferroelectric with the simplest structure, forming bosonic spin-zero bipolaron at RT, and it's dipoles respond to opto-electrical signals; therefore, this material holds significant promise for transforming the field of optoelectronics.

[27] arXiv:2508.02606 [中文pdf, pdf, html, 其他]

标题： 立方氮化硼-金刚石异质结构的界面结构和电子性质 显示英文标题

标题： Interface Structure and Electronic Properties in Cubic Boron Nitride - Diamond Heterostructures

Cody L. Milne, Hector Gomez, Adway Gupta, A. Glen Birdwell, Sergey Rudin, Elias J. Garratt, Bradford B. Pate, Tony G. Ivanov, Arunima K. Singh, Mahesh R. Neupane

主题： 材料科学 (cond-mat.mtrl-sci)

立方氮化硼（cBN）与金刚石的异质界面由于其超宽禁带和小的晶格失配（$\sim1.5$%），在高功率和高频电子器件中展现出有前景的进展，引起了广泛关注。 然而，这种异质界面的实现受到生长条件的挑战和对界面性质理解不足的限制。 在本工作中，我们采用密度泛函理论，研究了金刚石/cBN异质结构的结构和电子性质，作为界面化学计量、cBN厚度以及表面终止和钝化的函数。 形成能和界面键长表明，硼终止的异质结最为稳定，而突然的氮终止异质结最不稳定，但可以通过碳混合来稳定。 使用杂化泛函计算了异质结构的能带结构，我们发现突然的硼终止和氮终止异质结分别表现出$p$型和$n$型导电性，而碳混合的异质结保持宽的绝缘带隙（$4.2-4.4$eV）。 发现突然界面的有效质量随化学计量强烈变化。 有趣的是，电荷分析显示，在界面两侧出现了二维电子或空穴气体区域，其密度高达$10^{14}$cm$^{-2}$，具有明显的空间定位。 能带对齐显示，类型I和类型II的能带偏移可通过界面组成进行调节。 进一步分析能带对齐表明，金刚石价带始终比cBN价带高$0.25-2.1$eV。 有趣的是，界面终止类型会改变金刚石导带相对于cBN导带的相对位置，表现出从类型I到类型II的能带对齐转变。 显示英文摘要

Heterointerfaces of cubic boron nitride (cBN) with diamond have garnered significant interest due to their ultra-wide bandgaps and small lattice mismatch ($\sim1.5$\%), offering promising advancements in high-power and high-frequency electronic devices. However, the realization of this heterointerface has been limited by challenging growth conditions and insufficient understanding of interfacial properties. In this work, we employ density-functional theory to investigate the structural and electronic properties of diamond/cBN heterostructures as a function of interfacial stoichiometry, cBN thickness, and surface termination and passivation. Formation energies and interfacial bond lengths reveal that boron-terminated heterojunctions are the most stable while abrupt nitrogen-terminated heterojunctions are least stable, but can be stabilized by carbon-mixing. Bandstructures are computed for the heterostructures using hybrid functionals, where we find the abrupt boron-terminated and nitrogen-terminated heterojunctions exhibit $p$-type and $n$-type conductivity, respectively, while carbon-mixed heterojunctions retain wide insulating bandgaps ($4.2-4.4$ eV). The effective masses of the abrupt interfaces are found to vary strongly with stoichiometry. Intriguingly, charge analysis reveals two-dimensional electron or hole gas regions with ultra-high densities on the order of $10^{14}$ cm$^{-2}$, with distinct spatial localization on either side of the interface. Band alignments show type-I and type-II band offsets tunable by interfacial composition. Further analysis of the band alignments reveals that the diamond valence bands consistently lie above the cBN valence bands by $0.25-2.1$ eV. Interestingly, the interface termination type switches the relative conduction band position of diamond relative to the cBN conduction band, exhibiting a type-I to type-II band alignment transition.

交叉提交 (展示 17 之 17 条目 )

[28] arXiv:2508.00833 (交叉列表自 cs.CE) [中文pdf, pdf, html, 其他]

标题： 基于生成对抗网络的闭环电极微结构设计的深度核贝叶斯优化方法 显示英文标题

标题： Deep Kernel Bayesian Optimisation for Closed-Loop Electrode Microstructure Design with User-Defined Properties based on GANs

Andrea Gayon-Lombardo, Ehecatl A. del Rio-Chanona, Catalina A. Pino-Munoz, Nigel P. Brandon

评论： 此作品是博士论文的一部分，可在帝国理工学院档案馆中找到：https://spiral.imperial.ac.uk/entities/publication/8301132d-83a7-4b1d-a0fd-aa752781c512

主题： 计算工程、金融与科学 (cs.CE) ; 材料科学 (cond-mat.mtrl-sci) ; 机器学习 (cs.LG)

生成具有最佳形态和传输特性的多相多孔电极微观结构对于改进电化学储能设备的设计至关重要，例如锂离子电池。 电极特性通过作为电化学反应与传输过程发生的主要场所而直接影响电池性能。 本工作提出了一种生成-优化闭环算法，用于设计具有定制特性的微观结构。 使用深度卷积生成对抗网络作为深度内核，并用于生成多孔锂离子电池阴极材料的合成三相三维图像。 高斯过程回归利用生成器的潜在空间，并作为代理模型来关联合成微观结构的形态和传输特性。 该代理模型被集成到深度内核贝叶斯优化框架中，该框架根据生成器的潜在空间优化阴极特性。 定义了一组目标函数以实现形态特性（例如，体积分数、比表面积）和传输特性（相对扩散率）的最大化。 我们展示了同时最大化相关特性（比表面积和相对扩散率）以及这些特性的约束优化的能力。 这是在感兴趣相的体积分数保持恒定值的情况下对形态或传输特性进行最大化。 可视化优化后的潜在空间揭示了其与形态特性之间的相关性，从而能够快速生成具有定制特性的视觉上逼真的微观结构。 显示英文摘要

The generation of multiphase porous electrode microstructures with optimum morphological and transport properties is essential in the design of improved electrochemical energy storage devices, such as lithium-ion batteries. Electrode characteristics directly influence battery performance by acting as the main sites where the electrochemical reactions coupled with transport processes occur. This work presents a generation-optimisation closed-loop algorithm for the design of microstructures with tailored properties. A deep convolutional Generative Adversarial Network is used as a deep kernel and employed to generate synthetic three-phase three-dimensional images of a porous lithium-ion battery cathode material. A Gaussian Process Regression uses the latent space of the generator and serves as a surrogate model to correlate the morphological and transport properties of the synthetic microstructures. This surrogate model is integrated into a deep kernel Bayesian optimisation framework, which optimises cathode properties as a function of the latent space of the generator. A set of objective functions were defined to perform the maximisation of morphological properties (e.g., volume fraction, specific surface area) and transport properties (relative diffusivity). We demonstrate the ability to perform simultaneous maximisation of correlated properties (specific surface area and relative diffusivity), as well as constrained optimisation of these properties. This is the maximisation of morphological or transport properties constrained by constant values of the volume fraction of the phase of interest. Visualising the optimised latent space reveals its correlation with morphological properties, enabling the fast generation of visually realistic microstructures with customised properties.

[29] arXiv:2508.00876 (交叉列表自 cs.LG) [中文pdf, pdf, 其他]

标题： 一种数据驱动的机器学习方法用于预测钢结构货架柱的轴向承载能力 显示英文标题

标题： A Data-Driven Machine Learning Approach for Predicting Axial Load Capacity in Steel Storage Rack Columns

Bakhtiyar Mammadli, Casim Yazici, Muhammed Gürbüz, İrfan Kocaman, F. Javier Dominguez-Gutierrez, Fatih Mehmet Özkal

主题： 机器学习 (cs.LG) ; 材料科学 (cond-mat.mtrl-sci)

在本研究中，我们提出了一种机器学习（ML）框架，用于预测冷成型钢结构构件的轴向承载能力（kN）。该方法强调稳健的模型选择和可解释性，解决了传统分析方法在捕捉屈曲行为固有非线性和几何复杂性方面的局限性。数据集包括钢柱的关键几何和机械参数，经过适当的预处理步骤，包括删除无信息标识符和填补缺失值。评估了一系列回归算法，从线性模型到基于核的回归器和集成树方法。其中，梯度提升回归在多个指标（包括决定系数（R2）、均方根误差（RMSE）和平均绝对误差（MAE））上表现出优越的预测性能，因此被选为最终模型。通过SHapley Additive exPlanations（SHAP）解决模型可解释性问题，从而深入了解影响预测轴向承载力的输入特征的相对重要性和相互作用。为了便于实际部署，该模型通过Streamlit集成到交互式、基于Python的网络界面中。该工具允许终端用户——如结构工程师和设计师——手动输入设计参数或通过CSV上传，并在无需编程专业知识的情况下获得轴向承载力的实时预测。应用于钢制货架柱的背景下，该框架展示了数据驱动工具如何增强设计安全性，简化验证工作流程，并在屈曲是关键失效模式的结构应用中支持决策制定。 显示英文摘要

In this study, we present a machine learning (ML) framework to predict the axial load-bearing capacity, (kN), of cold-formed steel structural members. The methodology emphasizes robust model selection and interpretability, addressing the limitations of traditional analytical approaches in capturing the nonlinearities and geometrical complexities inherent to buckling behavior. The dataset, comprising key geometric and mechanical parameters of steel columns, was curated with appropriate pre-processing steps including removal of non-informative identifiers and imputation of missing values. A comprehensive suite of regression algorithms, ranging from linear models to kernel-based regressors and ensemble tree methods was evaluated. Among these, Gradient Boosting Regression exhibited superior predictive performance across multiple metrics, including the coefficient of determination (R2), root mean squared error (RMSE), and mean absolute error (MAE), and was consequently selected as the final model. Model interpretability was addressed using SHapley Additive exPlanations (SHAP), enabling insight into the relative importance and interaction of input features influencing the predicted axial capacity. To facilitate practical deployment, the model was integrated into an interactive, Python-based web interface via Streamlit. This tool allows end-users-such as structural engineers and designers, to input design parameters manually or through CSV upload, and to obtain real-time predictions of axial load capacity without the need for programming expertise. Applied to the context of steel storage rack columns, the framework demonstrates how data-driven tools can enhance design safety, streamline validation workflows, and inform decision-making in structural applications where buckling is a critical failure mode

[30] arXiv:2508.00894 (交叉列表自 astro-ph.IM) [中文pdf, pdf, html, 其他]

标题： 用于可持续月球制造的PEEK/月球土壤复合材料的增材制造 显示英文标题

标题： Additive Manufacturing of PEEK/Lunar Regolith Composites for Sustainable Lunar Manufacturing

Mohammad Azami, Pierre-Lucas Aubin-Fournier, Mehdi Hojjati, Krzysztof Skonieczny

主题： 天体物理学的仪器与方法 (astro-ph.IM) ; 地球与行星天体物理学 (astro-ph.EP) ; 材料科学 (cond-mat.mtrl-sci)

随着人类在NASA的阿尔忒弥斯计划下向长期月球存在迈进，基于月球的制造和建造（LBMC）能力的开发变得越来越关键。 从地球运输材料的高成本使得原位资源利用（ISRU）至关重要，月壤作为有前景的本地原料。 增材制造（AM）由于其几何灵活性、材料效率以及按需、特定地点生产的潜力，为LBMC提供了一个有吸引力的平台。 本研究探讨了含有10至50 wt%月壤模拟物（LRS）的聚醚醚酮（PEEK）复合材料的材料挤出（MEX）AM。 PEEK和LMS-1D粉末通过双螺杆挤出进行熔融复合，使用高温腔体打印，并在300摄氏度下退火。样品通过密度测量、热分析、拉伸测试以及显微结构和元素映射进行表征。 所有丝材均表现出高于96%的密度，尽管打印后的孔隙率从纯PEEK中的不到1%增加到50 wt% LRS时的7.5%，这是由于熔体粘度升高所致。 添加月壤提高了结晶度（17.4至20.5%）和弹性模量（提高6-41%），同时减少了分层和变形，从而提高了尺寸精度和打印成功率。 拉伸强度从107 MPa逐渐下降到40 wt% LRS时的90 MPa，然后在50 wt%时急剧下降至约70 MPa。 退火对于含有最多30 wt% LRS的复合材料提高了密度和刚度，在更高含量时效果有限。 显微结构和元素分析证实了连续的PEEK基体和均匀分散的月壤颗粒。 这项工作确立了富含月壤的PEEK复合材料的加工窗口和权衡，支持未来月球基础设施的ISRU启用的AM。 显示英文摘要

As humanity advances toward long-term lunar presence under NASA's Artemis program, the development of lunar-based manufacturing and construction (LBMC) capabilities has become increasingly critical. The high cost of transporting materials from Earth makes in-situ resource utilization (ISRU) essential, with lunar regolith serving as a promising local feedstock. Additive manufacturing (AM) offers a compelling platform for LBMC due to its geometric flexibility, material efficiency, and capacity for on-demand, site-specific production. This study investigates material extrusion (MEX) AM of polyether-ether-ketone (PEEK) composites containing 10 to 50 wt% lunar regolith simulant (LRS). PEEK and LMS-1D powders were melt-compounded via twin-screw extrusion, printed using a high-temperature chamber, and annealed at 300 degrees C. The samples were characterized through density measurements, thermal analysis, tensile testing, and microstructural and elemental mapping. All filaments exhibited densities above 96%, though as-printed porosity increased from less than 1% in neat PEEK to 7.5% at 50 wt% LRS due to elevated melt viscosity. Regolith incorporation enhanced crystallinity (17.4 to 20.5%) and elastic modulus (by 6-41%), while reducing delamination and warping, which improved dimensional accuracy and print success rates. Tensile strength declined gradually from 107 MPa to 90 MPa up to 40 wt% LRS, then dropped sharply to approximately 70 MPa at 50 wt%. Annealing improved density and stiffness for composites containing up to 30 wt% LRS, with marginal benefit at higher contents. Microstructural and elemental analyses confirmed a continuous PEEK matrix with uniformly dispersed regolith particles. This work establishes processing windows and trade-offs for regolith-rich PEEK composites, supporting ISRU-enabled AM of future lunar infrastructure.

[31] arXiv:2508.00896 (交叉列表自 cs.CV) [中文pdf, pdf, 其他]

标题： 相分数引导的去噪扩散模型，用于通过显微图像-掩码对合成增强多相钢显微结构分割 显示英文标题

标题： Phase-fraction guided denoising diffusion model for augmenting multiphase steel microstructure segmentation via micrograph image-mask pair synthesis

Hoang Hai Nam Nguyen, Minh Tien Tran, Hoheok Kim, Ho Won Lee

主题： 计算机视觉与模式识别 (cs.CV) ; 材料科学 (cond-mat.mtrl-sci)

机器学习在金相显微结构分割中的有效性通常受到缺乏人工标注的相位掩码的限制，尤其是在金属合金中的稀有或成分复杂的形态方面。 我们引入了PF-DiffSeg，一种相位分数控制的一阶段去噪扩散框架，在单一生成轨迹中联合合成显微结构图像及其对应的分割掩码，以进一步提高分割准确性。 通过基于全局相位分数向量进行条件控制，该向量被增强以表示真实数据分布并强调少数类，我们的模型生成成分有效且结构一致的显微结构图像和掩码样本，从而提高数据多样性和训练效率。 在增材制造多相钢的MetalDAM基准上进行评估，与标准增强策略相比，我们的合成增强方法在少数类中显著提高了分割准确性，并且在减少推理时间的同时，还优于两阶段的掩码引导扩散和生成对抗网络（GAN）基线。 该方法将生成和条件控制整合到一个统一的框架中，为金相应用中的数据增强提供了一个可扩展的解决方案。 显示英文摘要

The effectiveness of machine learning in metallographic microstructure segmentation is often constrained by the lack of human-annotated phase masks, particularly for rare or compositionally complex morphologies within the metal alloy. We introduce PF-DiffSeg, a phase-fraction controlled, one-stage denoising diffusion framework that jointly synthesizes microstructure images and their corresponding segmentation masks in a single generative trajectory to further improve segmentation accuracy. By conditioning on global phase-fraction vectors, augmented to represent real data distribution and emphasize minority classes, our model generates compositionally valid and structurally coherent microstructure image and mask samples that improve both data diversity and training efficiency. Evaluated on the MetalDAM benchmark for additively manufactured multiphase steel, our synthetic augmentation method yields notable improvements in segmentation accuracy compared to standard augmentation strategies especially in minority classes and further outperforms a two-stage mask-guided diffusion and generative adversarial network (GAN) baselines, while also reducing inference time compared to conventional approach. The method integrates generation and conditioning into a unified framework, offering a scalable solution for data augmentation in metallographic applications.

[32] arXiv:2508.01068 (交叉列表自 physics.chem-ph) [中文pdf, pdf, html, 其他]

标题： 学习分子动力学长时间步模拟的动作 显示英文标题

标题： Learning the action for long-time-step simulations of molecular dynamics

Filippo Bigi, Michele Ceriotti

评论： 12页，5图

主题： 化学物理 (physics.chem-ph) ; 材料科学 (cond-mat.mtrl-sci) ; 机器学习 (stat.ML)

经典力学的方程可以用来模拟从天体物理到原子尺度的无数物理系统的随时间演化。 精确的数值积分需要较小的时间步长，这限制了计算效率——尤其是在分子动力学等涉及极大不同时间尺度的情况下。 使用机器学习（ML）算法来预测轨迹可以使积分时间步长显著延长，但会引入诸如能量不守恒和系统不同自由度之间均分能量丧失等伪影。 我们提出学习数据驱动的结构保持（辛和时间可逆）映射来生成长时间步的经典动力学，并表明这种方法等价于学习感兴趣系统的力学作用量。 我们表明，由作用量导出的ML积分器消除了非结构保持ML预测器的病态行为，并且该方法可以迭代应用，作为计算成本较低的直接预测器的修正方法。 显示英文摘要

The equations of classical mechanics can be used to model the time evolution of countless physical systems, from the astrophysical to the atomic scale. Accurate numerical integration requires small time steps, which limits the computational efficiency -- especially in cases such as molecular dynamics that span wildly different time scales. Using machine-learning (ML) algorithms to predict trajectories allows one to greatly extend the integration time step, at the cost of introducing artifacts such as lack of energy conservation and loss of equipartition between different degrees of freedom of a system. We propose learning data-driven structure-preserving (symplectic and time-reversible) maps to generate long-time-step classical dynamics, showing that this method is equivalent to learning the mechanical action of the system of interest. We show that an action-derived ML integrator eliminates the pathological behavior of non-structure-preserving ML predictors, and that the method can be applied iteratively, serving as a correction to computationally cheaper direct predictors.

[33] arXiv:2508.01232 (交叉列表自 quant-ph) [中文pdf, pdf, 其他]

标题： 原位Al2O3钝化外延钽和铝薄膜实现了超导微波谐振器的长期稳定性 显示英文标题

标题： In situ Al2O3 passivation of epitaxial tantalum and aluminum films enables long-term stability in superconducting microwave resonators

Yi-Ting Cheng, Hsien-Wen Wan, Wei-Jie Yan, Lawrence Boyu Young, Yen-Hsun Glen Lin, Kuan-Hui Lai, Wan-Sin Chen, Chao-Kai Cheng, Ko-Hsuan Mandy Chen, Tun-Wen Pi, Yen-Hsiang Lin, Jueinai Kwo, Minghwei Hong

评论： 21页，5图

主题： 量子物理 (quant-ph) ; 材料科学 (cond-mat.mtrl-sci)

超导微波谐振器的长期稳定性对于可扩展的量子技术至关重要；然而，表面和界面退化继续限制器件的稳定性。 在这里，我们展示了由外延钽和铝薄膜制成的微带谐振器的卓越稳定性，在超高真空下原位沉积的Al2O3保护下。 这些谐振器最初表现出内部品质因数（Qi）超过一百万，并且在空气中暴露长达十四个月后仍保持高性能，仅出现轻微退化。 相比之下，依赖于天然表面氧化物的器件随时间推移显示出Qi的显著下降，表明微波损耗增加。 X射线光电子能谱显示，原位沉积的Al2O3有效抑制了界面氧化，并保持了底层超导薄膜的化学完整性，而天然氧化物则允许逐步氧化，导致器件退化。 这些发现确立了一种坚固、可扩展的钝化策略，解决了超导量子电路开发中一个长期存在的材料挑战。 显示英文摘要

Long-term stability of superconducting microwave resonators is essential for scalable quantum technologies; however, surface and interface degradation continue to limit device stability. Here, we demonstrate exceptional stability in microstrip resonators fabricated from epitaxial tantalum and aluminum films, protected by in situ deposited Al2O3 under ultra-high vacuum. These resonators initially exhibit internal quality factors (Qi) exceeding one million and maintain high performance with minimal degradation after up to fourteen months of air exposure. In contrast, devices relying on native surface oxides show substantial declines in Qi over time, indicating increased microwave losses. X-ray photoelectron spectroscopy reveals that the in situ Al2O3 effectively suppresses interfacial oxidation and preserves the chemical integrity of the underlying superconducting films, whereas native oxides permit progressive oxidation, leading to device degradation. These findings establish a robust, scalable passivation strategy that addresses a longstanding materials challenge in the development of superconducting quantum circuits.

[34] arXiv:2508.01284 (交叉列表自 cond-mat.str-el) [中文pdf, pdf, html, 其他]

标题： 应变SrCoO$_3$薄膜中稳健铁磁性的混合自旋态 显示英文标题

标题： Mixed spin states for robust ferromagnetism in strained SrCoO$_3$ thin films

Xiquan Zheng, Nicholas B. Brookes, Flora Yakhou-Harris, Yingjie Lyu, Jianbing Zhang, Qian Xiao, Xinyi Jiang, Qingzheng Qiu, Qizhi Li, Shilong Zhang, Xinqiang Cai, Pu Yu, Yi Lu, Yingying Peng

评论： 6页，4图

主题： 强关联电子 (cond-mat.str-el) ; 材料科学 (cond-mat.mtrl-sci)

过渡金属氧化物中的外延应变可以引起电子和磁性性质的显著变化。 一项关于外延应变的SrCoO$_3$薄膜的最新研究揭示了在金属-绝缘体转变过程中持续的铁磁性。 这挑战了当前的理论预测，这种鲁棒性的局部自旋态的本质仍未解决。 在此，我们采用高分辨率共振非弹性X射线散射（RIXS）在Co-$L_3$边缘探测应变的SrCoO$_3$薄膜的自旋态。 与CoO$_6$集团多重态计算相比，我们确定了一个由高自旋和低自旋混合构型组成的基态，不同于之前提出的中间自旋态。 我们的结果表明，铁磁性的鲁棒性来源于这种混合自旋态与负电荷转移相关的配体空穴之间的相互作用。 这些发现为SrCoO$_3$中非平凡的磁性基态提供了直接的实验证据，并为设计关联氧化物中的鲁棒铁磁系统提供了新途径。 显示英文摘要

Epitaxial strain in transition-metal oxides can induce dramatic changes in electronic and magnetic properties. A recent study on the epitaxially strained SrCoO$_3$ thin films revealed persistent ferromagnetism even across a metal-insulator transition. This challenges the current theoretical predictions, and the nature of the local spin state underlying this robustness remains unresolved. Here, we employ high-resolution resonant inelastic x-ray scattering (RIXS) at the Co-$L_3$ edge to probe the spin states of strained SrCoO$_3$ thin films. Compared with CoO$_6$ cluster multiplet calculations, we identify a ground state composed of a mixed high- and low-spin configuration, distinct from the previously proposed intermediate-spin state. Our results demonstrate that the robustness of ferromagnetism arises from the interplay between this mixed spin state and the presence of ligand holes associated with negative charge transfer. These findings provide direct experimental evidence for a nontrivial magnetic ground state in SrCoO$_3$ and offer new pathways for designing robust ferromagnetic systems in correlated oxides.

[35] arXiv:2508.01367 (交叉列表自 cond-mat.supr-con) [中文pdf, pdf, html, 其他]

标题： 非平衡超导体中的超电流放大 显示英文标题

标题： Supercurrent Amplification in Nonequilibrium Superconductors

Qinghong Yang, Yuqi Cao, Dante M. Kennes, Zhiyuan Sun

评论： 5页，3图

主题： 超导性 (cond-mat.supr-con) ; 材料科学 (cond-mat.mtrl-sci) ; 强关联电子 (cond-mat.str-el)

在超快实验中，对超导体施加的泵浦激光脉冲通常会加热电子系统并抑制超流电子的密度。随后，由于电子-声子热化，电子经历冷却过程，使得超流密度随时间恢复。我们表明，如果在冷却过程中由探测脉冲引发超电流，则会出现一种引人注目的“超电流放大”现象，即净电流随超流密度的增加而随时间增长。我们利用玻尔兹曼动力学方程，揭示了其微观起源是准粒子通过杂质和声子的动量弛豫散射，这与普遍接受的认为杂质总是衰减电流的直觉形成鲜明对比。我们进一步表明，超电流放大具有重要的实验表现，包括超快迈斯纳效应和光学反射率超过一的现象。 显示英文摘要

In ultrafast experiments on superconductors, a pump laser pulse often heats up the electronic system and suppresses the density of superfluid electrons. Subsequently, the electrons undergo a cooling process due to electron-phonon thermalization so that the superfluid density recovers in time. We show that if a supercurrent is initiated by a probe pulse in the cooling process, an intriguing phenomenon of 'supercurrent amplification' occurs, meaning that the net current grows in time with the increasing superfluid density. Using the Boltzmann kinetic equation, we uncover its microscopic origin as the momentum-relaxing scattering of quasi-particles by impurities and phonons, in stark contrast to the widely accepted intuition that impurities always attenuate currents. We further show that supercurrent amplification has important experimental manifestations, including the ultrafast Meissener effect and an optical reflectivity exceeding unity.

[36] arXiv:2508.01383 (交叉列表自 quant-ph) [中文pdf, pdf, html, 其他]

标题： 弹性电子散射中的纠缠：微扰理论忽略了布拉格散射的基本方面 显示英文标题

标题： Entanglement in Elastic Electron Scattering: Perturbation theory misses fundamental aspects of Bragg scattering

Stefan Löffler, Peter Schattschneider

主题： 量子物理 (quant-ph) ; 材料科学 (cond-mat.mtrl-sci)

弹性电子散射是研究原子尺度材料的主要手段之一。 它通常通过将样品建模为固定、静态的微扰势来描述，从而完全忽略了内部原子的量子特性。 在本工作中，我们提出了弹性电子散射的量子处理方法。 我们表明，探测束与样品的相互作用会导致两个系统之间的纠缠，这可能产生深远的影响，尤其是在相干性和图像对比度方面。 作为一项及时的例子，我们讨论了纳米颗粒布拉格散射中的退相干现象。 我们还研究了在何种条件下可以恢复传统的散射理论。 显示英文摘要

Elastic electron scattering is one of the primary means of investigating materials on the atomic scale. It is usually described by modeling the sample as a fixed, static, perturbative potential, thereby completely neglecting the quantum nature of the atoms inside. In this work, we present a quantum treatment of elastic electron scattering. We show that the interaction of the probe beam and the sample results in entanglement between the two systems, which can have far-reaching consequences, particularly on coherence and image contrast. As a timely example, we discuss decoherence in Bragg scattering on nanoparticles. We also investigate under which conditions the conventional scattering theory is recovered.

[37] arXiv:2508.01391 (交叉列表自 cond-mat.soft) [中文pdf, pdf, html, 其他]

标题： 蠕变到破坏转变的力和几何特征在颗粒堆中 显示英文标题

标题： Force and geometric signatures of the creep-to-failure transition in a granular pile

Qing Hao, Luca Montoya, Elena Lee, Luke K. Davis, Cacey Stevens Bester

主题： 软凝聚态物理 (cond-mat.soft) ; 材料科学 (cond-mat.mtrl-sci) ; 统计力学 (cond-mat.stat-mech)

颗粒蠕变是由于颗粒尺度相互作用的无序性，导致颗粒堆积中组分的缓慢、低于屈服的运动。 尽管蠕变在无序材料中很普遍，但目前尚不清楚如何根据组分之间的力和相互作用最佳预测蠕变到失效的区域。 为解决这一差距，我们进行实验以探索光弹性圆盘准二维堆叠中的蠕变和失效，从而量化颗粒运动和颗粒尺度接触力网络。 通过受控的外部扰动，我们研究颗粒重排、力网络和空隙的出现和演化，以阐明蠕变和失效的特征。 令人惊讶的是，即使在没有粒子运动的情况下，力链结构仍然保持动态。 我们发现力链的位移提供了对更大规模的雪崩式破坏的指示。 我们揭示了这些力特征与堆叠中空隙几何形状之间的联系。 总体而言，我们的创新实验和分析加深了我们对颗粒系统中从蠕变到失效转变的机械和几何理解。 显示英文摘要

Granular creep is the slow, sub-yield movement of constituents in a granular packing due to the disordered nature of its grain-scale interactions. Despite the ubiquity of creep in disordered materials, it is still not understood how to best predict the creep-to-failure regime based on the forces and interactions among constituents. To address this gap, we perform experiments to explore creep and failure in quasi two-dimensional piles of photoelastic disks, allowing the quantification of both grain movements and grain-scale contact force networks. Through controlled external disturbances, we investigate the emergence and evolution of grain rearrangements, force networks, and voids to illuminate signatures of creep and failure. Surprisingly, the force chain structure remains dynamic even in the absence of particle motion. We find that shifts in force chains provide an indication to larger, avalanche-scale disruptions. We reveal connections between these force signatures and the geometry of the voids in the pile. Overall, our novel experiments and analyses deepen our mechanical and geometric understanding of the creep-to-failure transition in granular systems.

[38] arXiv:2508.01421 (交叉列表自 cond-mat.mes-hall) [中文pdf, pdf, 其他]

标题： 金属亲和性增强通过原位形成的平行有机金属一维链结中的电子传输 显示英文标题

标题： Metallophilicity Enhances Electron Transport through Parallel Organometallic 1D Chain Junctions Formed In Situ

Sigifredo Luna, Hannah E Skipper, Brent Lawson, Eric S Cueny, Maria Kamenetska

主题： 中尺度与纳米尺度物理 (cond-mat.mes-hall) ; 材料科学 (cond-mat.mtrl-sci)

我们揭示了金氰化物分子线在环境条件下在STM断开结尖端组装时，金氰化物分子线的长度与宽度比形成和电导中的金亲和相互作用的作用。 具体而言，我们通过包含可变数量的金氰化物AuCN单体重复单元的1D单链（AuCN）n以及通过相邻分子线并联的电子传输特征进行了识别。 当以串联方式结合时，破坏性量子干涉导致（AuCN）n 1D线中n=1-3时电导呈指数衰减。 但当以并联方式结合时，通过相邻链的金原子的金亲和耦合重新排列了电子态，并导致电导显著增强。 我们的工作表明，金属亲和性可以在结组装和电子传输特性中起到重要作用。 显示英文摘要

We reveal the role of aurophilic interactions in the formation and conductance of gold cyanide molecular wires of variable length-to-width ratios assembled at the tip of an STM break junction in ambient conditions. Specifically, we identify electron transport signatures through 1D single chains containing variable number of monomeric repeats of gold cyanide AuCN, linked in series (AuCN)n, and through adjacent molecular wires linked in parallel. When bound in series, destructive quantum interference causes an exponential decay of conductance in (AuCN)n 1D wires for n=1-3. But when bound in parallel, aurophilic coupling through the gold atoms of neighboring chains reorders electronic states and results in significant enhancement of conductance. Our work reveals that metallophilicity can play a significant role in junction assembly and electron transport characteristics.

[39] arXiv:2508.01584 (交叉列表自 cond-mat.mes-hall) [中文pdf, pdf, 其他]

标题： 扭曲电子学和二维过渡金属二硫属化物中的莫尔超晶格物理 显示英文标题

标题： Twistronics and moiré superlattice physics in 2D transition metal dichalcogenides

Dawei Zhai, Hongyi Yu, Wang Yao

主题： 中尺度与纳米尺度物理 (cond-mat.mes-hall) ; 材料科学 (cond-mat.mtrl-sci)

通过堆叠二维半导体过渡金属二硫属化物（TMDs）并具有扭转角度或晶格失配而形成的莫尔超晶格，为探索凝聚态物理中的许多前沿课题提供了多功能平台，具有前所未有的可调性，包括光学、拓扑和关联现象。 这一研究领域发展迅速，最近取得了大量令人兴奋的实验和理论进展。 本综述旨在提供对TMDs莫尔超晶格基本特性的概述，并突出该引人入胜领域中的一些重大突破。 显示英文摘要

The moir\'e superlattices formed by stacking 2D semiconducting transition metal dichalcogenides (TMDs) with twisting angle or lattice mismatch have provided a versatile platform with unprecedented tunability for exploring many frontier topics in condensed matter physics, including optical, topological and correlation phenomena. This field of study advances rapidly and a plethora of exciting experimental and theoretical progresses have been achieved recently. This review aims to provide an overview of the fundamental properties of TMDs moir\'e superlattices, as well as highlight some of the major breakthroughs in this captivating field.

[40] arXiv:2508.01963 (交叉列表自 physics.chem-ph) [中文pdf, pdf, 其他]

标题： 通过集成原子 d0/d10 电子结和微观 P/N 异质结来增强高熵光催化剂上的氢和甲烷形成 显示英文标题

标题： Boosting hydrogen and methane formation on a high-entropy photocatalyst by integrating atomic d0/d10 electronic junctions and microscopic P/N heterojunctions

Ho Truong Nam Hai, Jacqueline Hidalgo-Jiménez, Kaveh Edalati

期刊参考： 《国际氢能杂志》，第162卷，第150762页，2025年

主题： 化学物理 (physics.chem-ph) ; 材料科学 (cond-mat.mtrl-sci)

通过光催化过程形成如氢气（H2）和甲烷（CH4）等绿色能源载体，为解决环境和能源问题提供了一种清洁的方法。为了实现高效生成H2和CH4的光催化剂，本研究在具有d0/d10电子结的高熵氧化物（HEO）中引入了P/N异质结。该研究使用CuO作为P型半导体，以及包含d0（Ti、Zr、Nb、Ta）和d10（Zn）阳离子的HEO作为N型半导体。该材料在光学性能方面表现出改进，如光吸收、电荷迁移率和减少电子-空穴复合。两个概念的结合，原子尺度的d0/d10电子结和微尺度的P/N异质结，导致H2和CH4产量增强。特别是在异质结中部分去除空位后，光催化水分解产生的H2达到0.71 mmol/g.h，CO2转化产生的CH4达到2.40 umol/g.h，甲烷化选择性为72%。本研究的综合策略在开发用于清洁能源生产的活性异质结构催化剂方面具有很高的潜力。 显示英文摘要

The formation of green energy carriers such as hydrogen (H2) and methane (CH4) via photocatalytic processes provides a clean method for addressing environmental and energy issues. To achieve highly efficient photocatalysts for H2 and CH4 generation, the present work introduces the P/N heterojunctions in a high-entropy oxide (HEO) with d0/d10 electronic junctions. The study uses CuO as a P-type semiconductor and the HEO containing d0 (Ti, Zr, Nb, Ta) and d10 (Zn) cations as an N-type semiconductor. The material exhibits improvements in optical properties, such as light absorption, charge mobility and reduced electron-hole recombination. The integration of two concepts, atomic-scale d0/d10 electronic junctions and micro-scale P/N heterojunctions, leads to enhanced H2 and CH4 production. Particularly after the partial removal of vacancies in the heterojunction, H2 production from photocatalytic water splitting reaches 0.71 mmol/g.h, and CH4 evolution from CO2 conversion reaches 2.40 umol/g.h with 72% selectivity for methanation. The integrated strategy of this study has a high potential in developing active heterostructured catalysts for clean fuel production.

[41] arXiv:2508.01967 (交叉列表自 cond-mat.str-el) [中文pdf, pdf, html, 其他]

标题： 从三斜到三棱：弯曲蜂窝结构SrHfO$_{3}$基异质结构中的对称性调制Rashba效应 显示英文标题

标题： From trigonal to triclinic: Symmetry-tuned Rashba effects in buckled honeycomb SrHfO$_{3}$-based heterostructures

Okan Köksal

评论： 10页，8图

主题： 强关联电子 (cond-mat.str-el) ; 材料科学 (cond-mat.mtrl-sci)

通过利用对称性破缺和自旋-轨道耦合的相互作用，我们使用包含Hubbard$U$项的密度泛函理论（DFT）计算和基于Wannier的紧束缚（TB）模型，研究弯曲蜂窝结构（SrHfO$_3$）$_2$/（LaAlO$_3$）$_4$（111）超晶格中的Rashba自旋分裂。 在非中心对称的$P1$相中，靠近$M$和$K$点出现明显的 Rashba 类型分裂，并伴随着螺旋状的面内自旋结构，而中心对称的$P321$相保持自旋简并。 基于 Wannier 的紧束缚哈密顿量，通过局域自旋轨道耦合进行解析扩展，能够再现 DFT 的结果。 Rashba 系数为$\alpha_R = 0.34$eV$ \cdot$ Å 和能量$E_R = 29$meV 直接从 DFT 带结构中提取，使该系统处于中等强度的氧化物 Rashba 材料之中。 $\Gamma$-声子计算证实了$P1$结构的动态稳定性，结果揭示了对称性破缺和轨道间杂化在实现Rashba效应中的关键作用，这由增强的虚数次近邻跃迁和贝里曲率所支持。 这些发现确立了基于SrHfO$_3$的弯曲异质结构作为在氧化物基自旋电子器件中工程化Rashba效应的一个有前景的平台。 显示英文摘要

Harnessing the interplay of symmetry breaking and spin-orbit coupling, we investigate Rashba spin splitting in buckled honeycomb (SrHfO$_3$)$_2$/(LaAlO$_3$)$_4$(111) superlattices using density functional theory (DFT) calculations with a Hubbard $U$ term and a Wannier-based tight-binding (TB) model. In the non-centrosymmetric $P1$ phase, pronounced Rashba-type splitting emerges near the $M$ and $K$ points accompanied by a helical in-plane spin texture, while the centrosymmetric $P321$ phase remains spin-degenerate. A Wannier-based tight-binding Hamiltonian, extended analytically with on-site spin-orbit coupling, reproduces the DFT results. A Rashba coefficient of $\alpha_R = 0.34$ eV$ \cdot$ Angstrom and energy $E_R = 29$ meV are extracted directly from the DFT band structure placing the system among moderately strong oxide Rashba materials. $\Gamma$-phonon calculation confirms the dynamical stability of the $P1$ structure and the results reveal the critical role of symmetry breaking and inter-orbital hybridization in enabling Rashba effects, supported by enhanced imaginary second-nearest-neighbor hoppings and Berry curvature. These findings establish SrHfO$_3$-based buckled heterostructures as a promising platform for engineering Rashba effects in oxide-based spintronic devices.

[42] arXiv:2508.01979 (交叉列表自 cond-mat.str-el) [中文pdf, pdf, html, 其他]

标题： 带Hubbard修正的自旋交叉化学中Hund的J项的总能量基准测试 显示英文标题

标题： Benchmarking total energies with Hund's J terms in Hubbard-corrected spin-crossover chemistry

Lórien MacEnulty, João Paulo Almeida de Mendonça, Roberta Poloni, David D. O'Regan

评论： 7个图（附录中1个，SI中4个），2个表（SI中1个）

主题： 强关联电子 (cond-mat.str-el) ; 材料科学 (cond-mat.mtrl-sci) ; 化学物理 (physics.chem-ph) ; 计算物理 (physics.comp-ph)

在一系列四个八面体配位的Fe(II)自旋交叉分子中评估了Hund's J项在各种DFT+U+J修正对半局域自旋密度泛函理论的影响，这些分子跨越了配体场谱的共价端。 我们报告了通过最小跟踪线性响应确定的所有价原子子空间和相关自旋状态的Hubbard U和Hund's J参数的值，并分析了其趋势。 然后，我们系统地应用它们，通过简化的旋转不变Hubbard泛函，以寻找最简单的组合，从而相对于使用CASPT2/CC获得的结果得到可靠的绝热能量差异。 规范的、正号的Hund's J项在进一步提高DFT+U已经强大的获取准确能级的能力方面的失败，促使我们评估它们在寻求解释这种强共价系统中的静态相关现象时的局限性，并提出了改进的方向。 显示英文摘要

The effect of the Hund's J terms in various DFT+U+J corrections to semi-local spin-density functional theory is assessed for a series of four octahedrally coordinated Fe(II) spin-crossover molecules spanning the covalent end of the ligand field spectrum. We report values and analyze trends for the Hubbard U and Hund's J parameters determined via minimum-tracking linear response for all valence atomic subspaces and relevant spin states in these molecules. We then methodically apply them via simplified rotationally-invariant Hubbard functionals in search of the simplest combination to yield reliable adiabatic energy differences with respect to those obtained using CASPT2/CC. The observed failure of canonical, positively-signed Hund's J terms in furthering the already robust capacity of DFT+U to obtain accurate energetics prompts an evaluation of their limitations when seeking to account for the static correlation phenomena in such strongly covalent systems and suggests directions for their improvement.

[43] arXiv:2508.02090 (交叉列表自 cond-mat.mes-hall) [中文pdf, pdf, html, 其他]

标题： 自洽对称适应模型用于具有自旋-轨道耦合的多倍费米子 显示英文标题

标题： Symmetry-adapted models for multifold fermions with spin-orbit coupling

Koki Satow, Ai Yamakage

评论： 14页，3图

主题： 中尺度与纳米尺度物理 (cond-mat.mes-hall) ; 材料科学 (cond-mat.mtrl-sci)

多倍费米子，即由晶体对称性保护的具有多重简并性的准粒子，由于其大的拓扑电荷和独特的能带结构，表现出各种引人入胜的现象。 对其对外部刺激响应的全面理解仍然具有挑战性，特别是对于由非平移对称性保护的类型，其中各种自由度相互复杂耦合。 在这里，我们基于晶体对称性系统地构建了包含外部场的有效模型。 具体而言，我们在自旋-轨道耦合存在的情况下，为由空间群 I2$_1$3（编号~199）保护的三重费米子构建了一个$\boldsymbol{k} \cdot \boldsymbol{p}$模型，并推导了外部场的项。通过补充紧束缚模型，我们研究了磁场响应并揭示了磁单极子的对湮灭。 此外，我们为位于空间群 P$\bar{4}3n1'$（编号~218）中的八重费米子构建了一个$\boldsymbol{k} \cdot \boldsymbol{p}$模型，并包括其与外部场的耦合。 这项工作为推进多倍费米子外部场响应和输运现象的研究提供了坚实的理论基础，为探索其丰富的物理特性开辟了新的途径。 显示英文摘要

Multifold fermions, quasiparticles with multiple degeneracy protected by crystalline symmetries, exhibit a variety of intriguing phenomena stemming from their large topological charges and unique band structures. A comprehensive understanding of their response to external stimuli remains challenging, especially for types protected by nonsymmorphic symmetries where various degrees of freedom are intricately coupled. Here, we systematically construct effective models for multifold fermions that incorporate external fields based on crystalline symmetry. Specifically, we develop a $\boldsymbol{k} \cdot \boldsymbol{p}$ model for the threefold fermion protected by space group I2$_1$3 (No.~199) in the presence of spin--orbit coupling, and derive the terms for external fields. By complementing this with a tight-binding model, we investigate the magnetic field response and reveal the pair annihilation of magnetic monopoles. Furthermore, we construct a $\boldsymbol{k} \cdot \boldsymbol{p}$ model for the eightfold fermion in space group P$\bar{4}3n1'$ (No.~218), including its coupling to external fields. This work provides a robust theoretical foundation for advancing the study of external field responses and transport phenomena in multifold fermions, opening new avenues to explore their rich physics.

[44] arXiv:2508.02650 (交叉列表自 cond-mat.soft) [中文pdf, pdf, 其他]

标题： 一种直接空气捕集系统的设计与演示，通过水分驱动将CO2输送到水相中 显示英文标题

标题： Design and demonstration of a direct air capture system with moisture-driven CO2 delivery into aqueous medium

Justin Flory, Samantha Taylor, Shuqin Li, Sunil Tiwari, Garrett Cole, Amory Lowe, Lindsey Hamblin, Samuel Piorkowski, Matthew Ryan, Thiago Stangherlin Barbosa, Jason Kmon, Nick Lowery, Joel Eliston, Jason C. Quinn, John McGowen, Matthew D. Green, Klaus Lackner, Wim Vermaas

评论： 14页，11图。将提交至《能源与环境科学》

主题： 软凝聚态物理 (cond-mat.soft) ; 材料科学 (cond-mat.mtrl-sci) ; 其他凝聚态物理 (cond-mat.other)

一种由湿度驱动的空气捕集（DAC）系统被设计并展示。在一个层流罩中展示了一个实验室规模的系统，每天可提供约1克二氧化碳，并且在4.2平方米（面积表面）的跑道池中，在户外运行了一个小型试点规模的系统，每天可提供约100克二氧化碳。设计了延长的网管包，以包含具有高表面积的AER珠子，用于接触空气，并发现与较大的网袋相比，可将干燥和二氧化碳负载时间减少约4倍。尽管该系统是为培养光合微生物提供二氧化碳而设计的，但其潜在用途更为广泛，包括在食品和饮料行业使用二氧化碳、转化为燃料和化学品以及封存。基于当前结果的实际情景的技术经济评估为将二氧化碳捕获到碱性溶液中的成本为每吨670美元，以及从溶液中提取、纯化并压缩到15兆帕进行封存的额外成本每吨280美元。一个有抱负的情景模型，合理改进以开发具有4毫摩尔二氧化碳每克吸附剂和50重量%吸水率的AER吸附剂，这导致吸附剂在1小时内完成干燥和负载，显示了将二氧化碳捕获到碱性溶液中的成本可能达到每吨51美元，以及额外的每吨109美元以达到15兆帕进行封存。生命周期分析显示，这种有抱负的湿度驱动过程通过利用水蒸发的能量，比热和/或真空摆动DAC节省多达87%的能量；然而，吸附剂在亲水网包中吸收约330重量%的水分会导致用水量比热力学极限高约33倍，这强调未来的研究需要提高吸附剂的疏水性，同时保持并进一步增加所需的离子交换能力以结合二氧化碳。 显示英文摘要

A moisture-driven air capture (DAC) system was designed and demonstrated. A laboratory-scale system delivering ~1 g CO2 per day was demonstrated in a laminar flow hood and a small pilot-scale system that could deliver ~100 g CO2 daily was operated outdoors in a 4.2 m2 (areal surface area) raceway pond. Elongated mesh tube packets were designed to contain AER beads with high surface area for contacting the air and were found to reduce drying and CO2 loading time ~4-fold over larger mesh bags. Whereas this system was designed for CO2 delivery for cultivating photosynthetic microbes, its potential uses are much broader and include CO2 use in the food and beverage industry, conversion to fuels and chemicals, and sequestration. Techno-economic assessments for a practical scenario based on current results are \$670/tonne to capture CO2 into an alkaline solution and an additional \$280/tonne to extract CO2 from solution, purify and compress to 15 MPa for sequestration. An aspirational scenario modelling reasonable improvements to develop AER sorbents with a capacity of 4 mmol CO2 per gram of sorbent and water uptake of 50 wt.%, which leads to sorbent drying and loading within 1 h, shows a potential to reach \$51/tonne to capture CO2 into an alkaline solution and an additional \$109/tonne to get to 15 MPa for sequestration. Life cycle analysis shows the aspirational moisture-driven process uses up to 87% less energy than thermal and/or vacuum swing DAC by using energy from water evaporation; however, ~330 wt.% water uptake by the sorbent contained in a hydrophilic mesh packets leads to ~33-fold higher water use than the thermodynamic limits, which emphasizes future research is needed to increase sorbent hydrophobicity while maintaining and further increasing ion exchange capacity needed to bind CO2.

替换提交 (展示 27 之 27 条目 )

[45] arXiv:1901.00841 (替换) [中文pdf, pdf, html, 其他]

标题： 一种磁性紧束缚模型：过渡金属和钴纳米颗粒的表面特性 显示英文标题

标题： A magnetic tight-binding model: surface properties of transition metals and cobalt nanoparticles

Jacques R. Eone

主题： 材料科学 (cond-mat.mtrl-sci)

一些过渡金属的磁性和表面性质已在紧束缚近似下进行了研究，包括库仑相关性。 这些表面性质是在应用仅限于d带的电荷中性规则后计算得到的。 这种形式给出了包含离域sp态的电荷分布，与线性 muffin-tin 轨道计算结果一致。 它能够在不依赖总能量的情况下描述局部磁性、表面能和功函数。 本次研究集中在面心立方钴、体心立方铁、面心立方镍和面心立方铂表面的研究，以及面心立方钴纳米颗粒的探索。 显示英文摘要

The magnetic and surface properties of some transition metals have been investigated within the tight-binding approximation, including Coulomb correlations. These surface properties are calculated after applying a charge neutrality rule that is restricted to the d-band. This formalism gives a charge distribution containing delocalized sp-states in agreement with a linear muffin-tin orbital calculation. It enables the description of local magnetism, surface energies, and work functions without recourse to the total energy. The present investigation is focused on the study of fcc cobalt, bcc iron, fcc nickel, and fcc platinum surfaces, as well as an exploration of fcc cobalt nanoparticles.

[46] arXiv:2101.03911 (替换) [中文pdf, pdf, html, 其他]

标题： 紧束缚模型：d带近似的修正 显示英文标题

标题： Tight-binding model: correction of the d-band approximation

Jacques R. Eone

主题： 材料科学 (cond-mat.mtrl-sci)

当限制在d带近似时，电子结构是一种计算模型，对于描述过渡金属既高效又有用。 在不考虑离域的sp态的情况下，这种近似会导致错误的表面能、结合能以及对铁磁性过渡金属的不准确描述。 本工作比较了实施校正的复杂性与使用精确的sp-d方法的可能性。 基于第二矩近似的基本力场继续用于描述过渡金属中的相互作用。 相反，本研究提出了一种基于距离依赖的跳跃参数的简单且更准确的原子间势。 电荷分布和Stoner模型也进行了分析，以提供对用于描述铁磁金属和合金的紧束缚图景的适当校正。 显示英文摘要

The electronic structure, when restricted to the d-band approximation, is a computational model that is both efficient and useful for describing transition metals. In the absence of considering delocalized sp-states, this approximation gives rise to incorrect surface energies, binding energies, and an inaccurate description of ferromagnetic transition metals. The present work compares the complexity of implementing corrections with the possibility of using an accurate sp-d approach. Basic force fields based on the second moment approximation continue to be utilized for the description of interactions in transition metals. In contrast, the present study proposes an elementary and more accurate interatomic potential based on hopping parameters depending on distances. The charge distribution and the Stoner model are also analyzed to provide appropriate corrections to the tight-binding picture used to describe ferromagnetic metals and alloys.

[47] arXiv:2408.01830 (替换) [中文pdf, pdf, 其他]

标题： 反铁电铪至二维极限 显示英文标题

标题： Antiferroelectric Hafnia Down to the 2D Limit

Xin Li, Guodong Ren, Haidong Lu, Kartik Samanta, Amit Kumar Shah, Kai Huang, Pravan Omprakash, Yu Yun, Pratyush Buragohain, Huibo Cao, Yan Wu, Jordan A. Hachtel, Andrew R. Lupini, Miaofang Chi, Juan Carlos Idrobo, Evgeny Y. Tsymbal, Alexei Gruverman, Rohan Mishra, Xiaoshan Xu

主题： 材料科学 (cond-mat.mtrl-sci)

反铁电性是一种材料特性，其特征是电偶极子在反平行方向上自发有序。 反铁电体在能量存储、固态冷却和记忆技术中具有前景；然而，这些材料稀少，其可扩展性仍大多未被探索。 在本研究中，我们证明了单晶铪，一种无铅的与CMOS兼容的材料，在压缩应变条件下表现出反铁电性。 我们观察到单晶(111)取向的掺镧铪薄膜在氧化钇稳定氧化锆上的外延生长中存在反平行亚晶格极化和稳定的双滞回特性，并表明铪的反极正交相符合Kittel的反铁电模型。 值得注意的是，压缩应变增强了较薄的掺镧铪薄膜中的反铁电序，在二维极限下实现了前所未有的850 C的有序温度，突显了铪在先进反铁电器件中的潜力。 显示英文摘要

Antiferroelectricity is a material property characterized by alternating electric dipoles spontaneously ordered in antiparallel directions. Antiferroelectrics are promising for energy storage, solid-state cooling, and memory technologies; however, these materials are scarce, and their scalability remains largely unexplored. In this work, we demonstrate that single-crystalline hafnia, a lead-free CMOS-compatible material, exhibits antiferroelectricity under compressive-strain conditions. We observe antiparallel sublattice polarization and stable double-hysteresis in single-crystalline (111)-oriented epitaxial La-doped hafnia films grown on yttrium-stabilized zirconia and show that the antipolar orthorhombic phase of hafnia adheres to the Kittel model of antiferroelectricity. Notably, compressive strain strengthens the antiferroelectric order in thinner La-doped hafnia films, achieving an unprecedented 850 C ordering temperature in the two-dimensional limit, highlighting hafnia's potential for advanced antiferroelectric devices.

[48] arXiv:2412.19267 (替换) [中文pdf, pdf, 其他]

标题： 镍腔中声学声子阻尼的异常频率缩放特性，该腔体通过皮秒激光剥离工艺制造 显示英文标题

标题： Anomalous frequency scaling of acoustic phonon damping in nickel cavities fabricated by ps-laser delamination

Alba Viejo-Rodríguez, Andrea Rossetti, Marco Gandolfi, Yoav Urbina-Elgueta, Evgeny B. Modin, Svetlana Starikovskaia, Tat Loon Chng, Vasily Temnov, Maria Antonietta Vincenti, Daniele Brida, Paolo Vavassori, Nicolò Maccaferri

主题： 材料科学 (cond-mat.mtrl-sci) ; 应用物理 (physics.app-ph)

单次脉冲皮秒（ps）激光诱导分层允许直接从连续金属膜中生成悬浮膜，为控制由声波驱动的超快磁化动力学提供了一个有前景的平台。 使用皮秒超声方法，我们证明可以在分层腔中光学激发长寿命的低频声波。 同时，频率高于60GHz的模式表现出令人惊讶的快速阻尼，其遵循与预期的通过声子-声子散射介导的衰减不兼容的标度定律。 将分层腔的测量结果与接触基底的基准镍膜进行比较，我们将发现与分层过程引起的镍晶体结构变化相关联。 显示英文摘要

Single-shot picosecond (ps) laser induced delamination allows for the direct generation of suspended membranes from a continuous metallic film, offering a promising platform for control of ultrafast magnetization dynamics driven by acoustic waves. Using the picosecond-ultrasonics method, we demonstrate that long-lived low-frequency acoustic waves can be optically-excited in the delaminated cavities. At the same time, higher-frequency modes >60GHz exhibit a surprisingly fast damping, following a scaling law incompatible with the expected attenuation mediated by phonon-phonon scattering. Comparing measurements between delaminated cavities and a benchmark nickel film in contact with the substrate, we link our findings with structural modifications of the nickel crystal induced by the delamination process.

[49] arXiv:2503.14170 (替换) [中文pdf, pdf, html, 其他]

标题： 向确定SiC中的PL6中心：从第一性原理筛选到竞争缺陷候选者的超精细验证 显示英文标题

标题： Towards Identifying the PL6 Center in SiC: From First-Principles Screening to Hyperfine Validation of Competing Defect Candidates

Xin Zhao, Mingzhe Liu, Yu Chen, Qi Zhang, Chang-Kui Duan

主题： 材料科学 (cond-mat.mtrl-sci)

在4H-SiC中的PL6色心因其优异的室温自旋和光学特性而闻名，但其微观起源尚未明确。在本第一性原理研究中，我们系统地研究了潜在结构以阐明其性质。我们首先严格检验了DV-反位点假设（一个双空位与一个碳反位点配对，$\mathrm{C_{Si}}$），分析了各种$V_\mathrm{Si}V_\mathrm{C}+\mathrm{C_{Si}}$配置的能量、电子和自旋特性。在此框架下，两种具有$\mathrm{C_{3v}}$对称性的$\mathrm{kk+C_{Si}}$复合物成为强有力的候选者。随后，对这些候选者、替代的OV模型[具体为OV(hh)和OV(kk)，即氧取代C同时伴有Si空位]以及实验数据之间的超精细相互作用特征进行了关键比较。该分析表明，OV(hh)结构更能准确再现PL6的超精细特征。此外，重新评估针对相关PL5中心提出的OV(hk)模型时，发现其零场分裂参数$E$与实验结果存在不一致，这表明PL5和PL6可能有不同的起源。这些发现提供了重要的理论见解，并促使针对这些量子缺陷进行有针对性的实验验证。 显示英文摘要

The PL6 color center in 4H-SiC, known for its excellent ambient-temperature spin and optical properties, has an unresolved microscopic origin. In this first-principles study, we systematically investigate potential structures to clarify its nature. We first rigorously examine the DV-antisite hypothesis (a divacancy paired with a carbon antisite, $\mathrm{C_{Si}}$), analyzing the energetic, electronic, and spin properties of various $V_\mathrm{Si}V_\mathrm{C}+\mathrm{C_{Si}}$ configurations. Two $\mathrm{C_{3v}}$-symmetric $\mathrm{kk+C_{Si}}$ complexes emerge as strong candidates within this framework. Subsequently, a critical comparison of hyperfine interaction signatures is performed between these candidates, the alternative OV model [specifically OV(hh) and OV(kk), an oxygen replacing C together with a Si vacancy], and experimental data. This analysis demonstrates that the OV(hh) structure more accurately reproduces PL6's hyperfine features. Furthermore, re-evaluation of the proposed OV(hk) model for the related PL5 center reveals zero-field splitting parameter $E$ inconsistencies with experimental results, suggesting that PL5 and PL6 may have distinct origins. These findings provide crucial theoretical insights and motivate targeted experimental validation for these quantum defects.

[50] arXiv:2503.16274 (替换) [中文pdf, pdf, 其他]

标题： 利用热力学和显微结构减轻丸料还原模型中的过拟合 显示英文标题

标题： Using Thermodynamics and Microstructure to Mitigate Overfitting in Pellet Reduction Models

Ömer K. Büyükuslu, Fabrice Yang, Dierk Raabe, Moritz to Baben, Anna L. Ravensburg

主题： 材料科学 (cond-mat.mtrl-sci)

使用富氢气体直接还原铁正在迅速成为绿色钢铁生产的关键策略。 该过程涉及复杂的多尺度现象，包括固态相变和气体通过孔隙的传输，这些现象必须被准确表示以便进行预测性的工业应用。 在此，我们提出一个热力学合理的团块尺度模型，该模型描述了这些机制，并可作为改进H$_2$/CO含气氛中团块还原动力学理解的基础。 该模型假设气相保持热力学平衡，这意味着气体组成会立即适应系统中的任何变化。 与现有模型相比，这大大减少了拟合参数的数量，同时保持严格的热力学上限估计。 在反应速率方程中包含了一个驱动力项，该驱动力项基于平衡气体相中O$_2$的分压。 这种受约束的平衡方法确保在含碳气体中，铁氧化物的三个还原步骤以及石墨和渗碳体的形成只有在热力学上可行时才会发生。 证明仅基于转化度数据拟合动力学参数会导致过拟合。 这一点对于现有模型和此处介绍的模型都是成立的，尽管后者包含的参数更少。 为了解决这一过拟合问题，可以考虑关键还原阶段的空间分辨显微结构数据，如这里所示，针对在H$_2$气氛中还原的团块最近报道的数据。 显示英文摘要

Direct reduction of iron using hydrogen-rich gas is rapidly emerging as a key strategy for green steel production. This process involves complex, multiscale phenomena, encompassing solid-state phase transformations and gas transport through pores, that must be accurately represented for predictive industrial implementation. Here, we present a thermodynamically sound pellet-scale model that describes these mechanisms and can serve as a foundation for improving the understanding of pellet reduction kinetics in H$_2$/CO-containing atmospheres. The model assumes that the gas phase remains in thermodynamic equilibrium, meaning that the composition of the gas instantaneously adjusts to any changes in the system. This reduces the number of fitting parameters drastically compared to other existing models, while maintaining a strict thermodynamic upper bound estimate. A driving force term is included in the reaction rate equation based on the partial pressure of O$_2$ in the equilibrated gas phase. This constrained equilibrium-based approach ensures that the three iron oxide reduction steps and the formation of graphite and cementite in carbon-containing gases occur only if they are thermodynamically possible. It is demonstrated that fitting kinetic parameters based on conversion degree data alone leads to overfitting. This is true both for existing models and the model introduced here, despite the fact that the latter contains fewer parameters. To overcome this overfitting problem, spatially resolved microstructural data at key reduction stages can be considered, as shown here for recently reported data for a pellet reduced in H$_2$ atmosphere.

[51] arXiv:2506.12319 (替换) [中文pdf, pdf, html, 其他]

标题： 横向热电学的基本原理和进展 显示英文标题

标题： Fundamentals and advances in transverse thermoelectrics

Hiroto Adachi, Fuyuki Ando, Takamasa Hirai, Rajkumar Modak, Matthew A. Grayson, Ken-ichi Uchida

评论： 32页，11图，1表

主题： 材料科学 (cond-mat.mtrl-sci) ; 应用物理 (physics.app-ph)

横向热电效应由于时间反演对称性或结构对称性的破坏，在正交方向上相互转换电荷和热量电流，使得在单一材料中能够实现简单且多用途的热能收集和固态冷却/加热。 与传统塞贝克效应和帕尔帖效应所需的复杂模块结构相比，横向热电效应提供了完整的器件结构，有可能解决热电转换性能多模块退化的基本问题。 本文综述文章概述了目前所有已知的横向热电转换现象和原理及其特性，并以统一的方式对其进行重新分类。 横向热电发电机、冰箱和主动冷却器的性能被公式化，表明热边界条件在讨论其行为中起着关键作用。 还介绍了横向热电领域的最新应用研究和材料开发实例，并讨论了未来的发展前景。 显示英文摘要

Transverse thermoelectric effects interconvert charge and heat currents in orthogonal directions due to the breaking of either time-reversal symmetry or structural symmetry, enabling simple and versatile thermal energy harvesting and solid-state cooling/heating within single materials. In comparison to the complex module structures required for the conventional Seebeck and Peltier effects, the transverse thermoelectric effects provide the complete device structures, potentially resolving the fundamental issue of multi-module degradation of thermoelectric conversion performance. This review article provides an overview of all currently known transverse thermoelectric conversion phenomena and principles, as well as their characteristics, and reclassifies them in a unified manner. The performance of the transverse thermoelectric generator, refrigerator, and active cooler is formulated, showing that thermal boundary conditions play an essential role to discuss their behaviors. Examples of recent application research and material development in transverse thermoelectrics are also introduced, followed by a discussion of future prospects.

[52] arXiv:2507.12776 (替换) [中文pdf, pdf, 其他]

标题： 低温下拉伸应变超薄钇铁石榴石中可调磁各向异性的磁化动力学 显示英文标题

标题： Cryogenic magnetization dynamics in tensile-strained ultrathin yttrium iron garnets with tunable magnetic anisotropy

Jihyung Kim, Dongchang Kim, Seung-Gi Lee, Yung-Cheng Li, Jae-Chun Jeon, Jiho Yoon, Sachio Komori, Ryotaro Arakawa, Tomoyasu Taniyama, Stuart S. P. Parkin, Kun-Rok Jeon

评论： 19页，7图

主题： 材料科学 (cond-mat.mtrl-sci) ; 中尺度与纳米尺度物理 (cond-mat.mes-hall)

我们报告了在通过脉冲激光沉积生长的拉伸应变超薄Y3Fe5O12（YIG）薄膜中，低温阻尼损耗显著减少，表现出超低阻尼常数和可调磁各向异性。比较宽带FMR测量结果显示，在Gd3Sc2Ga3O12（GSGG）上的拉伸应变YIG薄膜即使在纳米厚度和低温下仍保持低阻尼，优于在Gd3Ga5O12上的松弛薄膜。基于静态磁化测量和微结构表征，我们将这些增强的动态特性归因于YIG/GSGG界面处的互扩散被抑制，这是由于Sc的存在增强了化学稳定性和有利的生长动力学。我们的研究结果突显了化学和动力学因素在实现具有可忽略低温阻尼耗散和垂直磁各向异性的几纳米厚YIG薄膜中的重要性，这对于低温自旋电子学应用具有重要意义。 显示英文摘要

We report a significant reduction of low-temperature damping losses in tensile-strained, ultrathin Y3Fe5O12 (YIG) films grown by pulsed laser deposition, exhibiting ultralow damping constants and tunable magnetic anisotropy. Comparative broadband FMR measurements show that tensile-strained YIG films on Gd3Sc2Ga3O12 (GSGG) retain low damping even at nanometer thicknesses and cryogenic temperatures, outperforming relaxed films on Gd3Ga5O12. Based on static magnetometry measurements and microstructural characterization, we attribute these enhanced dynamic properties to the suppression of interdiffusion across the YIG/GSGG interface, resulting from enhanced chemical stability and favorable growth kinetics by the presence of Sc. Our findings highlight the importance of chemical and kinetic factors in achieving few-nanometer-thick YIG film with negligible low-temperature damping dissipation and perpendicular magnetic anisotropy for cryogenic spintronic applications.

[53] arXiv:2507.21673 (替换) [中文pdf, pdf, 其他]

标题： 电化学驱动的金属间化合物Cu3ZnLi2的形成改变了纳米结构双金属电池阳极中的锂传输 显示英文标题

标题： Electrochemically-driven formation of Intermetallic Cu3ZnLi2 alters Li-transport in nanostructured bimetallic battery anode

Eric V. Woods (1), Xinren Chen (1), Yuwei Zhang (1), J. Manoj Prabhakar (1), Patricia Jovičević-Klug (1), Matic Jovičević-Klug (1), Mahander P. Singh (1), Yujun Zhao (1), Siyuan Zhang (1), Stefan Zaefferer (1), Jian Liu (2), Yug Joshi (1), Baptiste Gault (1 and 3) ((1) Max Planck Institute for Sustainable Materials, Düsseldorf, Germany, (2) University of British Columbia, Kelowna, Canada, (3) Imperial College London, London, UK)

评论： 31页，12图，1表。通讯作者：Eric V. Woods（e.woods@mpi-susmat.de），Yug Joshi（y.joshi@mpi-susmat.de），Baptiste Gault（b.gault@mpi-susmat.de）

主题： 材料科学 (cond-mat.mtrl-sci)

锂基电池在社会电气化中的作用不可低估，然而其使用寿命通常受到枝晶形成的影响，即锂的局部沉积可能导致两个电极之间的短路，从而导致电池失效。无阳极锂金属电池可以使用纳米晶体双金属集流体，以改善锂的镀覆并限制或抑制枝晶的形成。在此，我们证明了在无阳极锂金属电池中使用的α-黄铜集流体（Cu 63% Zn 37%）的微观结构在循环过程中会发生演变。它在抛光后最初具有约80 nm厚的纳米晶体变形层。经过100次循环后，初始变形的黄铜层部分转化为一种三元Laves相Cu3ZnLi2，该相位于纳米晶体黄铜基体中，厚度增长至200-250 nm。在锂剥离过程中，该相部分电化学分解，但剩余的部分可以捕获锂，从而形成“死锂”，进而导致容量损失。我们提出了一个包括动态再结晶和相形成的微观结构演变机制。由于这种三元Laves相仅在电化学循环过程中出现，必须在不同循环条件下评估二元合金集流体是否会产生亚稳三元相，以稳定并利用这些相或将它们电化学完全剥离。 显示英文摘要

The role of Li-based batteries in the electrification of society cannot be understated, however their operational lifetime is often limited by the formation of dendrites, i.e. the localised deposition of Li that can cause shorts between the two electrodes leading to the failure of the battery. Nanocrystalline bimetallic current collectors can be used for anode-free Li-metal batteries, with improved Li plating and limited or suppressed formation of dendrites. Here, we demonstrate that the microstructure of an alpha-Brass current collector, Cu 63% Zn 37%, used in an anode-free Li-metal battery evolves during cycling. It initially had a nanocrystalline deformation layer approximately 80 nm in thickness after polishing. After 100 cycles, the initial deformed brass layer was partially converted to a ternary Laves phase Cu3ZnLi2 within a nanocrystalline brass matrix that grew to 200 - 250 nm in thickness. Upon Li stripping, the phase partially decomposes electrochemically, but what remains can sequester Li thus forming "dead Li" thereby contributing to capacity loss. We propose a mechanism for the microstructural evolution including dynamic recrystallization and phase formation. Since this ternary Laves phase emerges during electrochemical cycling alone, binary alloy current collectors must be assessed for metastable ternary phase formation under different cycling conditions to either stabilize and exploit such phases or electrochemically fully strip them.

[54] arXiv:2507.23647 (替换) [中文pdf, pdf, html, 其他]

标题： 三硒化物薄膜在太阳能收集中的结构无序和电子-声子相互作用的光谱特征 显示英文标题

标题： Spectroscopic Signatures of Structural Disorder and Electron-Phonon Interactions in Trigonal Selenium Thin Films for Solar Energy Harvesting

Rasmus S. Nielsen, Axel G. Medaille, Arnau Torrens, Oriol Segura-Blanch, Seán R. Kavanagh, David O. Scanlon, Aron Walsh, Edgardo Saucedo, Marcel Placidi, Mirjana Dimitrievska

主题： 材料科学 (cond-mat.mtrl-sci)

硒由于其不可抗拒的简单组成和有利的宽禁带，作为多种光电和能源应用的元素半导体正重新受到关注。 然而，其高挥发性和低辐射效率使得评估结构和光电质量变得具有挑战性，需要先进的非破坏性表征方法。 在本工作中，我们采用封闭空间封装策略以防止测量过程中的降解，并实现对振动和光电特性的灵敏探测。 通过温度依赖的拉曼和光致发光光谱，我们研究了在不同实验室中在名义上相同条件下合成的硒薄膜中的生长内应力、振动动力学以及电子-声子相互作用。 我们的结果表明，短程结构无序并非材料的固有特性，而是对细微加工变化高度敏感，这强烈影响电子-声子耦合和非辐射复合。 我们发现，这种结构无序和生长内应力可能促进扩展缺陷的形成，这些缺陷作为主要的非辐射复合中心，限制了光伏器件中的载流子寿命和开路电压。 这些发现表明，通过精确控制合成和后沉积处理，硒薄膜的光电质量可以显著提高，为通过有针对性地控制结晶动力学和微观结构无序来优化基于硒的薄膜技术指明了一条清晰的路径。 显示英文摘要

Selenium is experiencing renewed interest as a elemental semiconductor for a range of optoelectronic and energy applications due to its irresistibly simple composition and favorable wide bandgap. However, its high volatility and low radiative efficiency make it challenging to assess structural and optoelectronic quality, calling for advanced, non-destructive characterization methods. In this work, we employ a closed-space encapsulation strategy to prevent degradation during measurement and enable sensitive probing of vibrational and optoelectronic properties. Using temperature-dependent Raman and photoluminescence spectroscopy, we investigate grown-in stress, vibrational dynamics, and electron-phonon interactions in selenium thin films synthesized under nominally identical conditions across different laboratories. Our results reveal that short-range structural disorder is not intrinsic to the material, but highly sensitive to subtle processing variations, which strongly influence electron-phonon coupling and non-radiative recombination. We find that such structural disorder and grown-in stress likely promote the formation of extended defects, which act as dominant non-radiative recombination centers limiting carrier lifetime and open-circuit voltage in photovoltaic devices. These findings demonstrate that the optoelectronic quality of selenium thin films can be significantly improved through precise control of synthesis and post-deposition treatments, outlining a clear pathway toward optimizing selenium-based thin film technologies through targeted control of crystallization dynamics and microstructural disorder.

[55] arXiv:2402.15999 (替换) [中文pdf, pdf, 其他]

标题： 自旋密度波中巡回磁畴壁和准粒子边界态的发现 显示英文标题

标题： Discovery of Itinerant Magnetic Domain Wall and Quasiparticle Boundary State in Spin-Density-Waves

Yining Hu, Xu Wang, Chen Chen, Qingle Zhang, Dongming Zhao, Tianzhen Zhang, Chenxi Wang, Qiang-Hua Wang, Donglai Feng, Tong Zhang

评论： 25页，15图，包含补充材料

主题： 强关联电子 (cond-mat.str-el) ; 中尺度与纳米尺度物理 (cond-mat.mes-hall) ; 材料科学 (cond-mat.mtrl-sci)

常规磁畴壁的特点是局部自旋的重新取向。 然而，巡游磁体边界发生的情况在很大程度上尚不清楚。 在这里，我们使用对自旋敏感的扫描隧道显微镜，研究了典型巡游反铁磁体——铬（Cr）中自旋密度波（SDW）态的微观畴壁结构。 在两个不同调制的SDW畴边界处，我们发现自旋发生了有限尺度的衰减，而不是重新取向。 这产生了一个双-Q SDW态，进一步由伴随的二阶电荷调制所证实。 在共格SDW畴中，观察到了明显的SDW能隙。 有趣的是，由螺旋位错诱导的SDW半涡旋和反涡旋，通过反相畴壁成对出现。 在这样的反相畴壁处，自旋密度消失。 值得注意的是，我们首次在边界处观察到了类似于超导体中Andreev束缚态的SDW准粒子态。 这些独特的SDW边界结构可以看作是两个SDW局部干涉的结果，无论是不同Q值还是相反相位。 我们的发现揭示了一种不同于局域磁矩磁性的新型畴壁，其机制源于SDW的巡游特性。 显示英文摘要

Conventional magnetic domain walls are characterized by reorientation of local spins. However, what occurs at the boundary of itinerant magnets is largely unknown. Here using spin-sensitive scanning tunneling microscopy, we investigated the microscopic domain wall structure of the spin-density-wave (SDW) state in a prototypical itinerant antiferromagnet - chromium (Cr). At the boundary of two incommensurate SDW domains, we found the spins undergo finite-scale decay rather than reorientation. This generates a double-Q SDW state, which is further evidenced by an accompanying second-order charge modulation. In the commensurate SDW domains, a clear SDW energy gap is observed. Interestingly, the screw dislocations induced half vortex and anti-vortex of SDW, paired by antiphase domain wall. The spin density vanished at such antiphase domain walls. Remarkably, for the first time we observed the SDW quasiparticle states at the boundary, resembling the Andreev bound states in superconductors. These unique SDW boundary structures can be viewed as consequences of local interference of two SDWs, either with different Q or reversed phases. Our findings thus reveal a new type of domain wall distinct to that of local moment magnetism, with a mechanism rooted in the itinerant nature of SDW.

[56] arXiv:2406.11180 (替换) [中文pdf, pdf, html, 其他]

标题： 内在非线性电流的正确定义 显示英文标题

标题： Proper Definition of Intrinsic Nonlinear Current

Cong Xiao, Jin Cao, Qian Niu, Shengyuan A. Yang

主题： 中尺度与纳米尺度物理 (cond-mat.mes-hall) ; 材料科学 (cond-mat.mtrl-sci)

我们证明了三种常用于定义相同直流（或低频）本征线性反常霍尔响应的方法，实际上在本征非线性输运中会导致不同的结果。这种差异是由于本征反常分布（IAD）引起的。它来源于散射过程中的非线性场效应，但其值与散射完全无关，因为它代表电子波包与场修正能量的局部平衡。实验中可检测的本征电流的正确定义必须包含IAD的影响。我们还表明，IAD对于与基本物理关系的一致性是必不可少的。此外，我们预测在交流驱动下，整流和双频通道中的本征响应表现出不同的频率依赖性，我们估计了可以在反铁磁CuMnAs中探测到的信号。 显示英文摘要

We show that the three commonly employed approaches that define the same dc (or low-frequency) intrinsic linear anomalous Hall response actually lead to different results for intrinsic nonlinear transport. The difference is due to an intrinsic anomalous distribution (IAD). It originates from a nonlinear field effect during scattering, but its value is completely independent of scattering, because it represents the local equilibration of electron wave packets with field corrected energy. The proper definition of intrinsic current that is detectable in experiment must incorporate the effect of IAD. We also show that IAD is indispensable for consistency with fundamental physical relations. In addition, we predict that under ac driving, the intrinsic reponses in rectified and double-frequency channels exhibit distinct frequency dependence, for which we estimate the signals that can be probed in antiferromagnetic CuMnAs.

[57] arXiv:2412.10888 (替换) [中文pdf, pdf, html, 其他]

标题： 可调耦合、拓扑结构和手性通过磁性多层中的反磁子 显示英文标题

标题： Tunable Coupling, Topology, and Chirality by Antimagnons in Magnetic Multilayer

Yifan Liu, Zehan Chen, Qiming Shao

评论： 28页，15图

主题： 中尺度与纳米尺度物理 (cond-mat.mes-hall) ; 材料科学 (cond-mat.mtrl-sci)

在磁振子系统中实现新颖的拓扑状态，为鲁棒、低功耗的自旋波器件提供了可能。 在本文中，我们表明，包含左手自旋波（反磁子）从根本上重新组织了能带拓扑，并实现了可调的自旋波耦合和手性。 我们提出了一种二维Su-Schrieffer-Heeger类似模型，即2D-SSH4链，在该模型中，磁子和反磁子之间的偶极相互作用产生了具有非零陈数的拓扑能带。 这个框架解释了铁磁多层结构中拓扑表面态的起源，并表明它们与经典磁静力表面自旋波具有相同拓扑起源。 我们的模型还为设计通过偶极相互作用连接的更复杂的磁性多层结构提供了一个直接的框架，例如反铁磁/铁磁多层结构。 在这些偶极耦合的多层结构中，通过外部磁场和自旋扭矩可以调节层分辨的手性和相干以及耗散的层间自旋波耦合。 我们的结果为拓扑磁振子学提供了一个实用的平台，使未来器件中的磁子手性和耦合得以控制。 显示英文摘要

Realizing novel topological states in magnonic systems unlocks robust, low-power spin-wave devices. In this letter, we show that incorporating left-handed spin waves (antimagnons) fundamentally reorganizes band topology, and enables tunable spin-wave coupling and chirality. We proposed a two-dimensional Su-Schrieffer-Heeger like model, the 2D-SSH4 chain, where dipolar interactions between magnons and antimagnons generate topological bands with nonzero Chern numbers. This framework explains the origin of topological surface states in ferromagnetic multilayer and shows they share the same topological origin as classic magnetostatic surface spin waves. Our model also offers a straightforward framework for designing more complex magnetic multilayer connected by dipolar interactions, such as antiferromagnetic/ferromagnetic multilayer. In these dipolar-coupled multilayers, both coherent and dissipative interlayer spin-wave couplings together with the layer resolved chirality, are tunable via external magnetic fields and spin torques. Our results provide a practical platform for topological magnonics, enabling control of magnon chirality and coupling in future devices.

[58] arXiv:2502.15400 (替换) [中文pdf, pdf, html, 其他]

标题： 无常规磁体系统的超导现象 显示英文标题

标题： Superconducting phenomena in systems with unconventional magnets

Yuri Fukaya, Bo Lu, Keiji Yada, Yukio Tanaka, Jorge Cayao

评论： 特邀专题综述，57页，23图。发表版本

期刊参考： J. Phys.: 凝聚态物质 37, 313003 (2025)

主题： 超导性 (cond-mat.supr-con) ; 中尺度与纳米尺度物理 (cond-mat.mes-hall) ; 材料科学 (cond-mat.mtrl-sci)

在本工作中，我们回顾了由超导体和非常规磁体形成的结中超导现象的最新进展。 常规磁体，如铁磁体和反铁磁体，其特征是时间反演对称性被破坏，但由于自旋平行排列和动量中的自旋分裂能带，只有铁磁体产生有限的净磁化强度。 最近，一种新型磁体被报道，这里我们将它们称为非常规磁体，因为它们表现出铁磁体和反铁磁体的特殊性质：它们具有零净磁化强度（像反铁磁体）和非相对论的自旋分裂能带（像铁磁体），两者都导致各向异性的自旋极化费米面。 非常规磁体的一个有趣特性是它们的磁序相对于动量可以是偶数或奇数，其中$d$-波交替磁体和$p$-波磁体是最具代表性的例子。 在这方面，$d$-波交替磁体和$p$-波磁体分别被视为非常规$d$-和$p$-波超导态在磁学中的对应物。 虽然常规磁性对超导性的影响已被广泛研究，但非常规磁体与超导性的结合仅最近才引起相当大的关注。 本工作提供了对超导性与非常规磁体之间相互作用的最新进展的全面综述。 特别是，我们关注新兴的超导现象，并讨论其在量子应用方面的潜在意义。 显示英文摘要

In this work we review the recent advances on superconducting phenomena in junctions formed by superconductors and unconventional magnets. Conventional magnets, such as ferromagnets and antiferromagnets, are characterized by broken time-reversal symmetry but only ferromagnets produce a finite net magnetization due to parallel spin alignment and spin-split bands in momentum. Very recently, a new type of magnets has been reported and here we refer to them as unconventional magnets because they exhibit special properties of both ferromagnets and antiferromagnets: they exhibit zero net magnetization (like antiferromagnets) and a nonrelativistic spin splitting of energy bands (like ferromagnets), both leading to anisotropic spin-polarized Fermi surfaces. An interesting property of unconventional magnets is that their magnetic order can be even or odd with respect to momentum, where $d$-wave altermagnets and $p$-wave magnets are the most representative examples. In this regard, $d$-wave altermagnets and $p$-wave magnets are seen as counterparts in magnetism of the unconventional $d$- and $p$-wave superconducting states, respectively. While the impact of conventional magnetism on superconductivity has been largely studied, the combination of unconventional magnets and superconductivity has only lately attracted considerably attention. This work provides a comprehensive review of the recent progress on the interplay between superconductivity and unconventional magnets. In particular, we focus on the fundamental emerging superconducting phenomena and also discuss the potential implications towards quantum applications.

[59] arXiv:2502.19599 (替换) [中文pdf, pdf, 其他]

标题： 通过交换相互作用揭示超导电子气中的单轴自旋结构 显示英文标题

标题： Uniaxial spin texture in a superconducting electron gas revealed by exchange interactions

Junyi Yang, Changjiang Liu, Xianjing Zhou, Hanyu Hou, Kaijun Yin, Jianguo Wen, John Pearson, Alexey Suslov, Dafei Jin, Jidong S. Jiang, Ulrich Welp, Jian-Min Zuo, Michael R. Norman, Anand Bhattacharya

评论： 合稿（18页，5图）和补充信息（16页，18图和2表）

主题： 超导性 (cond-mat.supr-con) ; 中尺度与纳米尺度物理 (cond-mat.mes-hall) ; 材料科学 (cond-mat.mtrl-sci)

二维超导体具有自旋纹理的费米面，可以作为实现非常规配对态的平台，在量子信息科学和超导自旋电子学/轨道电子学领域具有重要研究价值。 我们在EuOx/KTaO3 (110)界面形成的二维电子气(2DEG)中观察到了一种不寻常的面内单轴各向异性，其中EuOx是磁性的。 这种各向异性在AlOx/KTaO3 (110)中并不明显，因为该覆盖层是非磁性的。 我们的结果与在KTaO3 (110)界面形成的2DEG中高度各向异性的“半-Rashba”自旋纹理费米面一致，由于轨道矩和自旋矩之间的近似抵消，这种费米面被外部磁场隐藏，但通过2DEG中的电子与EuOx/KTaO3 (110)界面附近的Eu矩之间的交换相互作用得以揭示。 单轴自旋纹理与磁性覆盖层之间的相互作用为探索磁性与二维超导性之间的相互作用提供了新方法。 显示英文摘要

Two-dimensional superconductors with spin-textured Fermi surfaces can be a platform for realizing unconventional pairing states and are of substantial interest in the context of quantum information science, and superconducting spintronics/orbitronics. We observed an unusual in-plane uniaxial anisotropy in the superconducting 2D electron gas (2DEG) formed at EuOx/KTaO3 (110) interfaces, where the EuOx is magnetic. This anisotropy is not evident in AlOx/KTaO3 (110) where the overlayer is non-magnetic. Our results are consistent with a highly anisotropic 'half-Rashba' spin-textured Fermi surface in 2DEGs formed at the KTaO3 (110) interface that is hidden from external magnetic fields due to a near cancellation between orbital and spin moments but revealed by exchange interactions of the electrons in the 2DEG with Eu moments near the EuOx/KTaO3 (110) interface. The interactions between the uniaxial spin texture and the magnetic overlayer offer new ways to explore the interplay between magnetism and 2D superconductivity.

[60] arXiv:2503.21209 (替换) [中文pdf, pdf, html, 其他]

标题： Rashba诱导的赝自旋-1晶格中的谷极化量子反常霍尔和拓扑金属相 显示英文标题

标题： Valley-polarized Quantum Anomalous Hall and Topological Metal Phase in Rashba induced pseudospin-1 lattice

Puspita Parui, Bheema Lingam Chittari

主题： 中尺度与纳米尺度物理 (cond-mat.mes-hall) ; 材料科学 (cond-mat.mtrl-sci)

我们研究了在交替电场和磁化的影响下，Rashba自旋-轨道耦合和交换耦合诱导的赝自旋-$1$体系Dice晶格的拓扑性质。 该体系的能带结构和拓扑相位被研究并与其赝自旋-$\frac{1}{2}$体系的蜂窝晶格进行比较。 在交替电场和磁化单独影响下，系统经历了一种明显的相变：(i) 交替电场使系统从量子反常霍尔$(C_n = 2)$转变为与边缘模式手性翻转相关的谷极化量子反常霍尔相$(C_n = -1)$；而 (ii) 交替磁化则使系统转变为与非常规反手性边缘带相关的拓扑金属，从拓扑绝缘体转变而来。 这些结果进一步得到了陈数相图、霍尔电导、锯齿形和扶手椅形边缘态计算的支持。 我们的发现增强了对二维赝自旋-$1$体系中新型拓扑相的理解，并为探索反手性边缘态开辟了一个新平台。 显示英文摘要

We study the topological properties of Rashba spin-orbit coupling and exchange coupling induced pseudospin-$1$ system Dice lattice under the influence of a staggered electric potential and magnetization. The band structure and topological phases of the system are investigated and compared with the pseudospin-$\frac{1}{2}$ system honeycomb lattice. Under individual influence of the staggered electric field and magnetization, the system undergoes a distinct phase transition: (i) a staggered electric potential drives the system from a quantum anomalous Hall $(C_n = 2)$ to a valley polarized quantum anomalous Hall phase $(C_n = -1)$ associated with edge modes with a flip in the chirality; while (ii) a staggered magnetization changes the system to a topological metal associated with unconventional antichiral edge bands, from a topological insulator. These results are further supported by calculations of the Chern phase diagrams, Hall conductance, zigzag, and armchair edge states. Our findings enhance the understanding of new topological phases in the 2D pseudospin-$1$ system and open up a new platform to explore the anti-chiral edge states.

[61] arXiv:2504.01709 (替换) [中文pdf, pdf, html, 其他]

标题： 手性振动如何驱动分子旋转 显示英文标题

标题： How chiral vibrations drive molecular rotation

Ivan Pasqua, Gregorio Staffieri, Michele Fabrizio

主题： 中尺度与纳米尺度物理 (cond-mat.mes-hall) ; 材料科学 (cond-mat.mtrl-sci)

我们分析两种简单的平面分子模型：一种具有D3对称性的离子分子，另一种具有D6对称性的共价分子。 这两种对称性都允许手性分子轨道和正常模的存在，这些正常模以Jahn-Teller方式相互耦合，并且在U(1)对称性下保持不变，其生成元为伪角动量。 在离子分子中，手性模具有电偶极矩但缺乏物理角动量，而在共价分子中情况则相反。 尽管如此，我们表明在两种情况下，手性模都可以通过圆偏振光被激发，并能够随后引起整个分子的旋转运动。 显示英文摘要

We analyze two simple model planar molecules: an ionic molecule with D3 symmetry and a covalent molecule with D6 symmetry. Both symmetries allow the existence of chiral molecular orbitals and normal modes that are coupled to each other in a Jahn-Teller manner, invariant under U (1) symmetry with generator a pseudo angular momentum. In the ionic molecule, the chiral mode possesses an electric dipole but lacks physical angular momentum, whereas, in the covalent molecule, the situation is reversed. In spite of that, we show that in both cases the chiral modes can be excited by a circularly polarized light and are subsequently able to induce rotational motion of the entire molecule.

[62] arXiv:2504.20958 (替换) [中文pdf, pdf, html, 其他]

标题： 软X射线动量显微术研究100纳米波长以下的非线性磁振子相互作用 显示英文标题

标题： Soft-X-ray momentum microscopy of nonlinear magnon interactions below 100-nm wavelength

Steffen Wittrock, Christopher Klose, Salvatore Perna, Korbinian Baumgaertl, Andrea Mucchietto, Michael Schneider, Josefin Fuchs, Victor Deinhart, Tamer Karaman, Dirk Grundler, Stefan Eisebitt, Bastian Pfau, Daniel Schick

评论： 附加文件包括展示MMM图像的视频，分别在（a）频率扫描和（b）功率扫描期间。

主题： 中尺度与纳米尺度物理 (cond-mat.mes-hall) ; 材料科学 (cond-mat.mtrl-sci)

磁振子代表长程有序自旋的量子化集体运动。 对于波长低于100纳米的情况，交换相互作用主导其物理性质，这导致了一个迄今为止尚未探索的非线性以及磁振子与其他准粒子之间耦合的领域。 除了选择性激发之外，这种短波长自旋波的检测仍然是当前研究和技术的一个挑战。 在这里，我们通过准弹性、共振软X射线散射来探测磁振子的强度和波矢。 这种磁振子动量显微术（MMM）可以在动量空间中以显著的灵敏度和高光子效率直接探测磁振子，频率范围可达太赫兹，波长可至几纳米。 这种基于光散射的技术获得的二维信息对于研究技术相关的薄膜样品中以交换为主的磁振子的非线性相互作用特别有价值。 在此过程中，我们揭示了丰富多样的深度非线性磁振子相互作用，突显了它们在新型计算方案中的潜力。 由于其固有的元素选择性和能够探测埋藏层的能力，软X射线MMM有潜力成为超宽带研究短波长磁子学的先进工具。 显示英文摘要

Magnons represent quantised collective motions of long-range ordered spins. For wavelength below 100 nm, exchange interactions dominate their physics, which gives rise to a so far unexplored regime of nonlinearities and couplings between magnons and other quasiparticles. Besides their selective excitation, also the detection of such short-wavelength spin waves remains a challenge of current research and technology. Here, we probe the intensity and wave vector of magnons by means of quasi-elastic, resonant soft-X-ray scattering. This Magnon Momentum Microscopy (MMM) can access magnons directly in momentum space with remarkable sensitivity and high photon efficiency up to THz frequencies and down to few-nanometre wavelengths. The two-dimensional information obtained by this light-scattering-based technique is especially valuable for studying the nonlinear interactions of exchange-dominated magnons within technologically relevant thin-film samples. In doing so, we uncover a rich variety of deeply nonlinear magnon interactions, highlighting their potential for applications in novel computing schemes. With its intrinsic element-selectivity and ability to probe also buried layers, soft-X-ray MMM has the potential to establish itself as an advanced tool for ultrabroadband studies of short-wavelength magnonics.

[63] arXiv:2505.06462 (替换) [中文pdf, pdf, html, 其他]

标题： 用于液体和材料性质的高效长程机器学习力场 显示英文标题

标题： Efficient Long-Range Machine Learning Force Fields for Liquid and Materials Properties

John L. Weber, Rishabh D. Guha, Garvit Agarwal, Yujing Wei, Aidan A. Fike, Xiaowei Xie, James Stevenson, Biswajit Santra, Richard A. Friesner, Karl Leswing, Mathew D. Halls, Robert Abel, Leif D. Jacobson

评论： 60页 10图

主题： 化学物理 (physics.chem-ph) ; 材料科学 (cond-mat.mtrl-sci)

机器学习力场（MLFFs）已成为一种先进的工具，用于成本高效的原子模拟，接近DFT精度，最近的消息传递MLFFs能够覆盖整个周期表。 我们提出了一种不变的消息传递MLFF架构（MPNICE），该架构迭代地预测原子部分电荷，包括长程相互作用，能够在实现与具有可比精度的模型相当的5-20倍更快的推理速度的同时，预测依赖电荷的性质。 我们为有机系统训练了直接和delta学习的MPNICE模型，并与液体和固体系统的实验性质进行对比测试。 我们还对有限系统的能量进行了对比测试，贡献了一个新的带有带电物种的扭转扫描集，以及一个用于TorsionNet500基准的新DLPNO-CCSD(T)参考集。 我们还训练并测试了用于块体无机晶体的MPNICE模型，重点在于结构排序和机械性能。 最后，我们探索了无机和有机系统的多任务模型，这些模型在特定领域任务上的表现略有下降，但表现出令人惊讶的泛化能力，稳定地预测了$\simeq500$Pt/Ir有机金属配合物的气相结构，尽管从未针对任何类型的有机金属配合物进行过训练。 显示英文摘要

Machine learning force fields (MLFFs) have emerged as a sophisticated tool for cost-efficient atomistic simulations approaching DFT accuracy, with recent message passing MLFFs able to cover the entire periodic table. We present an invariant message passing MLFF architecture (MPNICE) which iteratively predicts atomic partial charges, including long-range interactions, enabling the prediction of charge-dependent properties while achieving 5-20x faster inference versus models with comparable accuracy. We train direct and delta-learned MPNICE models for organic systems, and benchmark against experimental properties of liquid and solid systems. We also benchmark the energetics of finite systems, contributing a new set of torsion scans with charged species and a new set of DLPNO-CCSD(T) references for the TorsionNet500 benchmark. We additionally train and benchmark MPNICE models for bulk inorganic crystals, focusing on structural ranking and mechanical properties. Finally, we explore multi-task models for both inorganic and organic systems, which exhibit slightly decreased performance on domain-specific tasks but surprising generalization, stably predicting the gas phase structure of $\simeq500$ Pt/Ir organometallic complexes despite never training to organometallic complexes of any kind.

[64] arXiv:2505.13424 (替换) [中文pdf, pdf, html, 其他]

标题： 半经验量子力学的持久相关性 显示英文标题

标题： The Enduring Relevance of Semiempirical Quantum Mechanics

Jonathan E. Moussa

评论： 16页，4个图

主题： 化学物理 (physics.chem-ph) ; 材料科学 (cond-mat.mtrl-sci)

半经验模型的发展，以简化原子系统量子力学描述的做法，早在量子力学发现后不久就开始，并持续至今。 现在有许多用于原子模拟的方法，有许多软件实现和许多用户，其规模大到可以被视为一个软件市场。 在市场的早期阶段，半经验模型占据了很大的份额，但过去三十年来，原子模拟的研究活动逐渐向通用但昂贵的第一性原理量子力学方法和快速但专用的分子力学方法倾斜。 我从半经验建模的中间立场出发，对原子模拟的最新趋势提供一种观点，以学习其过去的成功并考虑其未来增长的可能路径。 特别是，有关于将半经验量子力学与机器学习模型相结合的大量正在进行的研究活动，以及第一性原理和半经验量子力学之间更紧密集成的一些未实现的可能性，需要更灵活的理论框架和更模块化的软件组件。 显示英文摘要

The development of semiempirical models to simplify quantum mechanical descriptions of atomistic systems is a practice that started soon after the discovery of quantum mechanics and continues to the present day. There are now many methods for atomistic simulation with many software implementations and many users, on a scale large enough to be considered as a software market. Semiempirical models occupied a large share of this market in its early days, but the research activity in atomistic simulation has steadily polarized over the last three decades towards general-purpose but expensive ab initio quantum mechanics methods and fast but special-purpose molecular mechanics methods. I offer perspective on recent trends in atomistic simulation from the middle ground of semiempirical modeling, to learn from its past success and consider its possible paths to future growth. In particular, there is a lot of ongoing research activity in combining semiempirical quantum mechanics with machine learning models and some unrealized possibilities of tighter integration between ab initio and semiempirical quantum mechanics with more flexible theoretical frameworks and more modular software components.

[65] arXiv:2506.10905 (替换) [中文pdf, pdf, html, 其他]

标题： $R$Co$_{2}$Al$_{8}$ ($R=$ La, Ce, Pr, Nd and Sm) 单晶的物理性质：各向异性 Kondo 晶格研究的一种新兴结构类型 显示英文标题

标题： Physical properties of $R$Co$_{2}$Al$_{8}$ ($R=$ La, Ce, Pr, Nd and Sm) single crystals: An emerging structure-type for anisotropic Kondo lattice studies

Fernando A. Garcia, Sushma Kumari, Juan Schmidt, Cris Adriano, Aashish Sapkota, Paul C. Canfield, Rebecca Flint, Raquel A. Ribeiro

评论： 13页，8图，发表于《物理评论B》

期刊参考： 物理评论B 111, 245160, 2025

主题： 强关联电子 (cond-mat.str-el) ; 材料科学 (cond-mat.mtrl-sci)

对基于稀土（$R$）的金属间材料进行系统研究是揭示一系列物理现象背后机制的一种主要策略，例如Kondo晶格的形成以及竞争的电子和磁各向异性。 在本工作中，展示了$R$Co$_{2}$Al$_{8}$（$R=$La, Ce, Pr, Nd 和 Sm）单晶体的磁性、热性和输运性质。 LaCo$_{2}$Al$_{8}$被表征为帕拉磁体，输运测量显示电流沿和垂直于正交$c$轴（$\rho_{c}$和$\rho_{ab}$，分别）时存在明显的电子各向异性，$\rho_{ab }\approx(4-7)\rho_{c }$在$300$K 时出现。我们表明 CeCo$_{2}$Al$_{8}$是一种库恩多晶格，从$\rho_{c}$和$\rho_{ab}$在$\approx$68 和 46 K 处的宽最大值推导出的库恩多相干温度$T_{\text{K}}^{*}$也是各向异性的。 这一发现与CeCo$_{2}$Al$_{8}$中可能的Kondo耦合各向异性有关。Pr和Nd基材料表现出强易轴各向异性（$c$轴）并在低于$T=4.84$K和$T=8.1$K时呈现反铁磁（AFM）有序。通过等温磁化测量研究了从这种AFM到自旋极化顺磁相态的巨磁转变。Sm基化合物也具有易轴AFM，在$T=21.6$K时发生转变。 显示英文摘要

Systematic investigations of rare-earth ($R$) based intermetallic materials are a leading strategy to reveal the underlying mechanisms governing a range of physical phenomena, such as the formation of a Kondo lattice and competing electronic and magnetic anisotropies. In this work, the magnetic, thermal and transport properties of $R$Co$_{2}$Al$_{8}$ ($R=$ La, Ce, Pr, Nd and Sm) single crystals are presented. LaCo$_{2}$Al$_{8}$ is characterized as a Pauli paramagnet and transport measurements, with the current along and perpendicular to the orthorhombic $c$-axis ($\rho_{c}$ and $\rho_{ab}$, respectively), reveal a clear electronic anisotropy, with $\rho_{ab }\approx(4-7)\rho_{c }$ at $300$ K. We show that CeCo$_{2}$Al$_{8}$ is a Kondo-lattice for which the Kondo coherence temperature $T_{\text{K}}^{*}$, deduced from broad maximums in $\rho_{c}$ and $\rho_{ab}$ at $\approx$ 68 and 46 K, respectively, is also anisotropic. This finding is related to a possible underlying anisotropy of the Kondo coupling in CeCo$_{2}$Al$_{8}$. The Pr- and Nd-based materials present strong easy-axis anisotropy ($c$-axis) and antiferromagnetic (AFM) orders below $T=4.84$ K and $T=8.1$ K, respectively. Metamagnetic transitions from this AFM to a spin-polarized paramagnetic phase state are investigated by isothermal magnetization measurements. The Sm-based compound is also an easy-axis AFM with a transition at $T=21.6$ K.

[66] arXiv:2507.05768 (替换) [中文pdf, pdf, html, 其他]

标题： 用定制光光流探测破坏的时间反演对称性 显示英文标题

标题： Probing broken time-reversal symmetry with tailored-light photocurrents

Daniel M. B. Lesko, Tobias Weitz, Simon Wittigschlager, Selina Nöcker, Weizhe Li, Peter Hommelhoff, Ofer Neufeld

评论： 13页，4图

主题： 光学 (physics.optics) ; 材料科学 (cond-mat.mtrl-sci)

光场驱动的光电流是生成无外部偏置的光电流的强大工具，在缺乏反演对称性的光-物质系统中尤为有效。 尽管这些光电流被用于电子应用，如电流源、开关和光伏，但它们的存在也可用于探测材料在平衡和非平衡状态下的性质，如拓扑性。 在此，我们通过利用定制激光场实现超快光电流生成，推进了光场驱动光电流光谱学的研究，以研究时间反演对称性（TRS）破缺相。 我们采用由双色线偏振激光束组成的组合，这些激光束各自尊重镜像（空间）和时间反演对称性，单独时排除光电流，但当组合在一起时可以打破对称性并产生光电流。 我们通过理论和实验表明，在TRS不变系统中，相对偏振角和双色相位的独特选择会施加一个禁止的光电流选择规则，因为定制的光保持TRS同时打破所有其他空间对称性。 随后，我们利用最先进的从头算模拟验证这一物理机制，并关键地预测在具有内在破坏TRS的材料中该机制会失效，从而为磁性和陈数物理创建一个无背景信号。 我们的工作为以超快时间分辨方式探测TRS破缺物质相铺平了道路，不需要应用外部磁场甚至圆偏振电场。 显示英文摘要

Light-field-driven photocurrents represent a powerful tool for generating photocurrents without external bias in light-matter systems that lack inversion symmetry. While these photocurrents are used in electronic applications, such as current sources, switches, and photovoltaics, their presence can also be used to probe material properties in and out of equilibrium, such as topology. Here we advance this path of light-field-driven photocurrent spectroscopy by utilizing tailored laser fields for ultrafast photocurrent generation to study time-reversal symmetry (TRS) broken phases. We employ combinations of bichromatic linearly-polarized laser beams that individually respect mirror (spatial) and time-reversal symmetry, individually precluding photocurrents, but when combined can break symmetries and generate photocurrents. We show, both theoretically and experimentally, that unique choices of the relative polarization angle and two-color phase imposes a forbidden photocurrent selection rule in TRS-invariant systems, as the tailored light maintains TRS while breaking all other spatial symmetries. We then employ state-of-the-art ab-initio simulations to validate this physical mechanism, and, crucially, predict its breaking in materials with intrinsically-broken TRS, creating a background free signal for magnetism and Chern physics. Our work paves way for probing TRS-broken phases of matter in an ultrafast time-resolved manner, not requiring the application of external magnetic fields or even circularly-polarized electric fields.

[67] arXiv:2507.16916 (替换) [中文pdf, pdf, 其他]

标题： 精确下折叠及其微扰近似 显示英文标题

标题： Exact downfolding and its perturbative approximation

Jonas B. Profe, Jakša Vučičević, P. Peter Stavropoulos, Malte Rösner, Roser Valentí, Lennart Klebl

评论： 13页，8图和6页附录

主题： 强关联电子 (cond-mat.str-el) ; 材料科学 (cond-mat.mtrl-sci) ; 统计力学 (cond-mat.stat-mech)

求解多电子问题，即使近似求解，也是当代凝聚态物理中最具挑战性的同时也是最重要的问题之一，与其它领域有各种联系。 标准的方法是采用一种分而治之的策略，结合各种数值和分析技术。 这一策略中的关键步骤是通过称为向下折叠的过程，为一组自由度导出一个有效模型，这通常对应于积分掉远离费米能级的能量尺度。 在本工作中，我们提出了这种向下折叠过程的严格公式，这补充了Honerkamp [PRB 85, 195129 (2012)] 提出的重整化群观点。 我们通过显式积分掉其余空间（例如高能自由度）来在一个任意选择的目标空间（例如低能自由度）中推导出一个精确的有效模型。 在这个形式框架下，我们陈述了条件，以证明将向下折叠的有效相互作用截断为少数低阶项的微扰方法是合理的。 此外，我们利用精确的形式框架正式推导出广泛使用的约束随机相位近似（cRPA），揭示了其潜在的近似，并在此过程中突出了相关的修正。 最后，我们详细描述了面心立方镍和无限层铜氧化物SrCuO$_2$这两种材料示例中的不同贡献。 我们的结果开辟了一条新的途径，可以以受控的方式获得有效模型，并判断所选目标空间是否合适。 显示英文摘要

Solving the many-electron problem, even approximately, is one of the most challenging and simultaneously most important problems in contemporary condensed matter physics with various connections to other fields. The standard approach is to follow a divide and conquer strategy that combines various numerical and analytical techniques. A crucial step in this strategy is the derivation of an effective model for a subset of degrees of freedom by a procedure called downfolding, which often corresponds to integrating out energy scales far away from the Fermi level. In this work we present a rigorous formulation of this downfolding procedure, which complements the renormalization group picture put forward by Honerkamp [PRB 85, 195129 (2012)}]. We derive an exact effective model in an arbitrarily chosen target space (e.g. low-energy degrees of freedom) by explicitly integrating out the the rest space (e.g. high-energy degrees of freedom). Within this formalism we state conditions that justify a perturbative truncation of the downfolded effective interactions to just a few low-order terms. Furthermore, we utilize the exact formalism to formally derive the widely used constrained random phase approximation (cRPA), uncovering underlying approximations and highlighting relevant corrections in the process. Lastly, we detail different contributions in the material examples of fcc Nickel and the infinite-layer cuprate SrCuO$_2$. Our results open up a new pathway to obtain effective models in a controlled fashion and to judge whether a chosen target space is suitable.

[68] arXiv:2507.22474 (替换) [中文pdf, pdf, html, 其他]

标题： 应变控制的二维交替磁体中的拓扑相变和陈数反转 显示英文标题

标题： Strain-Controlled Topological Phase Transitions and Chern Number Reversal in Two-Dimensional Altermagnets

Zesen Fu, Mengli Hu, Aolin Li, Haiming Duan, Junwei Liu, Fangping Ouyang

评论： 6页，4图

主题： 中尺度与纳米尺度物理 (cond-mat.mes-hall) ; 材料科学 (cond-mat.mtrl-sci)

我们提出了一项关于二维反磁体的理论和第一性原理研究，该反磁体表现出自旋-谷锁定和应变可调的拓扑相。 通过构建一个受反磁对称性约束的最小紧束缚模型，我们表明双轴应变可以驱动从平凡绝缘体到II型量子自旋霍尔（QSH）相的转变。 此外，我们推导出一种分析性的应变诱导扰动理论，该理论确定了两条临界曲线，将相空间分为四个区域，分别对应于平凡绝缘体、II型QSH相以及两种具有相反陈数的量子反常霍尔相。 值得注意的是，仅通过改变应变方向即可纯粹地反转陈数——而无需修改磁化或施加磁场。 该模型揭示了具有相同对称性和谷结构材料的通用相图。 对单层CrO的第一性原理计算证实了预测的拓扑转变，确立了应变工程作为二维反磁材料中拓扑控制的有效途径。 显示英文摘要

We present a theoretical and first-principles study of a two-dimensional altermagnet exhibiting spin-valley locking and strain-tunable topological phases. By constructing a minimal tight-binding model constrained by altermagnetic symmetry, we show that biaxial strain can drive a transition from a trivial insulator to a type-II quantum spin Hall (QSH) phase. Furthermore, we derive an analytical strain-induced perturbation theory that identifies two critical curves, dividing the phase space into four regions corresponding to a trivial insulator, a type-II QSH phase, and two quantum anomalous Hall phases with opposite Chern numbers. Remarkably, the Chern number can be reversed purely by changing the strain direction --without modifying magnetization or applying magnetic fields. The model reveals a universal phase diagram for materials with the same symmetry and valley structure. First-principles calculations on monolayer CrO confirm the predicted topological transitions, establishing strain engineering as an effective route for topological control in two-dimensional altermagnetic materials.

[69] arXiv:2507.23752 (替换) [中文pdf, pdf, html, 其他]

标题： 使用暗场X射线显微镜在向列畴中发现自发的介观应变波 显示英文标题

标题： Discovery of spontaneous mesoscopic strain waves in nematic domains using dark-field X-ray microscopy

Kaan Alp Yay, W. Joe Meese, Elliot Kisiel, Matthew J. Krogstad, Anisha G. Singh, Rafael M. Fernandes, Zahir Islam, Ian R. Fisher

评论： 53页，13图；2个参考文献的DOI信息已更新

主题： 强关联电子 (cond-mat.str-el) ; 材料科学 (cond-mat.mtrl-sci) ; 超导性 (cond-mat.supr-con)

电子向列相是一种关联物质相，其中低能电子态自发地破坏晶体晶格的离散旋转对称性。 电子向列相与具有相同对称性的应变之间的双线性耦合导致了一个单一的伪铁弹性相变，在此相变中，向列相和晶格应变同时出现。 为了最小化弹性能量，晶体形成结构孪晶域，每个域具有不同的向列方向取向（即，每个域具有诱导剪切应变的特定符号）。 尽管外部诱导应变对这些域的影响已被充分确立，但由于缺乏适当的实验工具，个体域内自发应变场的本征行为至今未被探索。 在此，我们报告了在欠掺杂铁基超导体的单个向列域中发现的自发介观应变波，这是通过暗场X射线显微镜（DFXM）观察到的。 该技术结合了高空间和倒易空间分辨率与全场、体敏感成像，能够直接可视化与向列序开始同时出现的亚域应变调制。 控制连续固体中非均匀应变的弹性兼容关系为我们在实验中观察到的应变波提供了自然机制。 我们的发现揭示了一种广泛相关的应变自组织形式，并将DFXM定位为一种强大的工具，用于探测晶格应变与电子序之间的局部相互作用。 显示英文摘要

Electronic nematic order is a correlated phase of matter in which low-energy electronic states spontaneously break a discrete rotational symmetry of a crystal lattice. Bilinear coupling between the electronic nematic and strains of the same symmetry yields a single pseudoproper ferroelastic phase transition at which both the nematic and lattice strain onset concurrently. To minimize elastic energy, the crystal forms structural twin domains, each with a distinct orientation of the nematic director (i.e. each with a specific sign of the induced shear strain). While the effects of externally induced strains on these domains are well established, the intrinsic behavior of spontaneous strain fields within individual domains has been hitherto unexplored, largely due to the lack of appropriate experimental tools. Here, we report the discovery of spontaneous mesoscopic strain waves within individual nematic domains of an underdoped iron-based superconductor, observed using dark-field X-ray microscopy (DFXM). This technique combines high spatial and reciprocal-space resolution with full-field, bulk-sensitive imaging, enabling direct visualization of subdomain strain modulations emerging concurrently with the onset of nematic order. The elastic compatibility relations that govern inhomogeneous strains in continuous solids provide a natural mechanism for the emergent strain waves that we observe. Our findings reveal a broadly relevant form of strain self-organization and position DFXM as a powerful tool for probing the local interplay between lattice strain and electronic order.

[70] arXiv:2507.23753 (替换) [中文pdf, pdf, html, 其他]

标题： 兼容的不稳定性：弹性理论的规范约束继承自电子向列临界性 显示英文标题

标题： Compatible Instability: Gauge Constraints of Elasticity Inherited by Electronic Nematic Criticality

W. Joe Meese, Rafael M. Fernandes

评论： 7页，3图，更新的参考链接

主题： 强关联电子 (cond-mat.str-el) ; 材料科学 (cond-mat.mtrl-sci) ; 超导性 (cond-mat.supr-con)

电子向列性在具有不同电子关联程度的量子材料中被广泛观察到，通过电荷、自旋、轨道或超导自由度表现出来。 一个能够描述这一大类系统的现象模型还必须考虑向列-弹性耦合，其中向列和弹性自由度相互交织。 然而，作为张量规范场理论，弹性必须满足兼容性关系，以保证晶格变形的可积性。 在这里，我们开发了一种明显尊重弹性兼容性关系的向列-弹性理论。 我们表明，这些约束将向列涨落的相空间分为两个正交的区域：一个兼容且因此临界，另一个不兼容且因此有能隙。 后者的抑制导致任何晶体晶格中的方向选择性向列临界性。 此外，临界的向列模式能够免受由微观缺陷应变引起的钉扎效应的影响，这些缺陷应变必然同时诱导纵向和横向相关的随机场。 最后，我们的结果还调和了看似矛盾的向列现象，例如向列相变的平均场特性以及畴结构的广泛存在。 显示英文摘要

Electronic nematicity is widely observed in quantum materials with varying degrees of electronic correlation, manifesting through charge, spin, orbital, or superconducting degrees of freedom. A phenomenological model capable of describing this broad set of systems must also account for nemato-elasticity, by which nematic and elastic degrees of freedom become intertwined. However, being a tensor gauge field theory, elasticity must satisfy the compatibility relations which guarantee the integrability of lattice deformations. Here, we develop a formalism for nemato-elasticity that manifestly respects the elastic compatibility relations. We show that these constraints bifurcate the phase space of nematic fluctuations into two orthogonal sectors: one compatible and thus critical, the other incompatible and therefore gapped. The suppression of the latter leads to universal direction-selective nematic criticality in any crystal lattice. Moreover, the critical nematic modes are protected from pinning effects induced by microscopic defect strains, which necessarily induce both longitudinal and transverse correlated random fields. Finally, our results also reconcile seemingly contradictory nematic phenomena, such as the mean-field character of the nematic transition and the widespread presence of domain formation.

[71] arXiv:2507.23754 (替换) [中文pdf, pdf, html, 其他]

标题： 电子向列临界理论的弹性相容性约束 显示英文标题

标题： Theory of Electronic Nematic Criticality Constrained by Elastic Compatibility

W. Joe Meese, Rafael M. Fernandes

评论： 37页，9图，更新的参考链接

主题： 强关联电子 (cond-mat.str-el) ; 材料科学 (cond-mat.mtrl-sci) ; 超导性 (cond-mat.supr-con)

电子向列相的定义性质——旋转对称性的自发破缺——意味着向列序参数与弹性应变场之间不可避免的耦合，称为向列-弹性耦合。 尽管这两个量都是二阶张量，但应变张量通过圣维南兼容性关系受到约束。 这三个耦合的二阶偏微分方程来源于晶格位移矢量作为势场的角色，并反映了几何变形的底层规范不变性，这种不变性仅在存在晶体缺陷时被破坏。 在本工作中，我们发展了一种通过共旋转螺旋基的理论来明确包含弹性兼容性的向列-弹性理论。 通过我们的形式化方法，我们表明弹性作用通过抑制不兼容的向列涨落，使向列序参数具有张量兼容性。 因此，向列-弹性耦合与原始的向列性有显著不同。 在没有缺陷的理想介质中，我们表明在不存在晶体各向异性的情况下，不兼容向列性的抑制导致方向选择性的临界性。 而在存在缺陷的系统中，我们表明弹性钉扎场来源于淬火缺陷，为局部向列序参数产生随机的纵向和横向共轭场。 方向选择性的向列临界性与来自随机场的钉扎效应的共存，在我们的理论中通过螺旋基的变换得到解释，这意味着局部实验探测向列性将受到长程和短程螺旋向列模式的线性但非局域组合的影响。 由于兼容性关系是各向同性介质中赋予的规范约束，我们的结果构成了所有晶体系统中向列-弹性临界性的普遍特征。 显示英文摘要

The defining property of electronic nematicity -- the spontaneous breaking of rotational symmetry -- implies an unavoidable coupling between the nematic order parameter and elastic strain fields, known as nemato-elasticity. While both quantities are rank-2 tensors, the strain tensor is constrained through the Saint Venant compatibility relations. These three coupled second-order partial differential equations arise from the lattice displacement vector's role as a potential field, and they reflect the underlying gauge invariance of geometric deformations which are violated only in the presence of crystalline defects. In this work, we develop a theory of nemato-elasticity that incorporates elastic compatibility explicitly through a co-rotating helical basis. With our formalism, we show elasticity bestows tensor compatibility upon the nematic order parameter by suppressing incompatible nematic fluctuations. As a result, nemato-elasticity is markedly different from bare nematicity. In ideal media devoid of defects, we show the suppression of incompatible nematicity underlies direction-selective criticality, even in the absence of crystalline anisotropy. In systems with defects, meanwhile, we show that elastic pinning fields emanate from quenched defects, generating random longitudinal and transverse conjugate fields for the local nematic order parameter. The coexistence of direction-selective nematic criticality with pinning effects from random fields is explained within our theory from the transformation to the helical basis, implying that local experimental probes of nematicity will be influenced by a linear -- but nonlocal -- combination of long-ranged and short-ranged helical nematic modes. Because the compatibility relations are gauge constraints endowed in the isotropic medium, our results constitute universal features of nemato-elastic criticality present in all crystalline systems.