标题： 由对称性破缺引起的FeSe拓扑结构 显示英文标题

标题： Symmetry-breaking-induced topology in FeSe

摘要： FeSe在过去二十年中一直是研究最深入的铁基超导体之一，表现出多种现象，如非常规超导性、向列序、磁性、轨道选择性关联和结构相变。 虽然在某些情况下已经识别出拓扑非平凡相——例如碲掺杂的FeSe和单层FeSe——但体相FeSe中的拓扑性质大多尚未被探索。 在这项工作中，我们提出了一种在体相FeSe中直接实现拓扑相的新途径。 我们证明，破坏面内$C_4$旋转对称性，从而降低晶体对称性，可以将FeSe带入强拓扑绝缘相。 为了支持这一点，我们进行了密度泛函理论计算，并使用拓扑量子化学和基于对称性的指标分析能带结构。 我们的结果表明，单轴应变和向正交低温相的结构转变都会导致非平凡的能带拓扑。 此外，通过动力学平均场理论引入电子关联表明，费米能级附近的拓扑特性保持稳健，因为相关能带仅经历适度的重整化。 这些发现突显了应变作为在FeSe中诱导拓扑相的一种有前景的机制。 显示英文摘要

摘要： FeSe has been one of the most intensively studied iron-based superconductors over the past two decades, exhibiting a wide range of phenomena such as unconventional superconductivity, nematic order, magnetism, orbital-selective correlations, and structural phase transitions. While topologically non-trivial phases have been identified in certain cases - such as Te-doped FeSe and monolayer FeSe - topology in bulk FeSe has largely remained unexplored. In this work, we propose a new route to realize topological phases directly in bulk FeSe. We demonstrate that breaking the in-plane $C_4$ rotational symmetry, thereby lowering the crystal symmetry, can drive FeSe into a strong topological insulating phase. To support this, we perform density functional theory calculations and analyze the band structure using topological quantum chemistry and symmetry-based indicators. Our results show that both uniaxial strain and the structural transition to the orthorhombic low-temperature phase lead to non-trivial band topology. Moreover, incorporating electronic correlations through dynamical mean field theory reveals that the topological characteristics near the Fermi level remain robust, as the relevant bands experience only moderate renormalization. These findings highlight strain as a promising mechanism to induce topological phases in FeSe.