AI 中文总结
本文通过紧束缚模型和线性响应理论，研究了铁轴性系统中局域晶格旋转诱导的电子响应，发现其产生特征性电四极矩且依赖于铁轴性序，为铁轴性态提供了独特的响应通道。
AI 中文摘要
我们利用二维方格上的紧束缚模型和线性响应理论，从理论上研究了铁轴性系统中电子对晶格形变的响应。虽然常规的弹性响应通常以对称应变来讨论，但位移梯度还包含一个描述局域晶格旋转的反对称分量。我们聚焦于这一旋转自由度，将对称应变和反对称局域旋转视为独立的微扰，并通过形变引起的电子跳跃振幅调制在微观上纳入它们的影响。我们发现，局域旋转会诱导出特征性的对角电四极矩，这些四极矩不同于由对称剪切应变产生的四极矩。旋转诱导的响应主要由带内贡献主导，并随铁轴性晶体场近似线性增加，在无铁轴性序时消失。相比之下，对称剪切诱导的响应在无铁轴性序时仍然有限，并同时包含带内和带间贡献。这些结果表明，反对称局域旋转提供了一条铁轴性态所特有的不同电子响应通道。
英文摘要
We theoretically investigate electronic responses to lattice deformation in a ferroaxial system using a tight-binding model on a two-dimensional square lattice and linear response theory. While conventional elastic responses are commonly discussed in terms of symmetric strain, the displacement gradient also contains an antisymmetric component describing a local lattice rotation. Focusing on this rotational degree of freedom, we treat the symmetric strain and antisymmetric local rotation as independent perturbations and incorporate their effects microscopically through deformation-induced modulations of the electronic hopping amplitudes. We find that the local rotation induces characteristic diagonal electric quadrupoles that are distinct from those generated by the symmetric shear strain. The rotation-induced response is dominated by the intraband contribution and increases approximately linearly with the ferroaxial crystal field, vanishing in the absence of ferroaxial order. In contrast, the symmetric-shear-induced response remains finite without ferroaxial order and contains both intraband and interband contributions. These results demonstrate that the antisymmetric local rotation provides a distinct electronic response channel characteristic of the ferroaxial state.
Comments5 pages, 3 figures
