标题： 扩展t-J模型在正方晶格上的非均匀态的性质 显示英文标题

标题： Nature of the inhomogeneous state of the extended t-J model on a square lattice

摘要： 我们进行变分蒙特卡罗计算，以研究空穴掺杂和电子掺杂的铜氧化物中的空间非均匀态。 通过使用Gutzwiller近似，我们考虑了来自电荷密度、自旋密度和配对场的激发，这些激发来自于t-J模型的平均场基态。 这导致了我们在包含电子-声子耦合引起的质量重整化的广义t-J型模型中数值发现的条纹图案。 在空穴掺杂侧，强的d波超导序导致形成了半掺杂反铁磁共振价键（AF-RVB）条纹，如著名的Yamada图所示。 另一方面，由于电子掺杂材料中的长程反铁磁序，在欠掺杂区域获得了一个具有“同相”磁畴（IPMD）的条纹结构，而不是AF-RVB条纹。 由晶格尺寸允许的最大周期的IPMD条纹在欠掺杂区域附近稳定，并排除了电子掺杂情况下的Yamada图。 基于我们可以达到的有限晶格尺寸，IPMD条纹的存在可能意味着电子掺杂化合物中的电子相分离，形成富电子和绝缘的半填充反铁磁长程有序区域。 显示英文摘要

摘要： We carry out the variational Monte Carlo calculation to examine spatially inhomogeneous states in hole- and electron-doped cuprates. By using Gutzwiller approximation, we consider the excitations, arising from charge density, spin density and pair field, of the mean-field ground state of the t-J model. It leads to the stripe patterns we have found numerically in a generalized t-J-type model including mass renormalization from the electron-phonon coupling. In the hole-doped side, a robust d-wave superconducting order results in the formation of the half-doped antiferromagnetic resonating-valence-bond (AF-RVB) stripes shown by the well-known Yamada plot. On the other hand, due to a long-range AF order in electron-doped materials, a stripe structure with the "in-phase" magnetic domain (IPMD) is obtained in the underdoped regime instead of the AF-RVB stripe. The IPMD stripe with the largest period permitted by lattice size is stabilized near the underdoped region and it excludes the Yamada plot from electron-doped cases. Based on finite lattice size to which we can reach, the existence of IPMD stripes may imply an electronic phase separation into an electron-rich and an insulating half-filled AF long-range ordered domains in electron-doped compounds.