扭曲材料中外在几何结构引起的旋光性
Gyrotropy from Extrinsic Geometry in Twisted Materials
- University of Pennsylvania（宾夕法尼亚大学）
机构由 AI 辅助整理，请以论文原文为准。
AI总结：
研究扭曲材料中外在几何结构引发的旋光性，通过一维导线阵列、双层石墨烯及双层MoTe2研究，发现旋光性与电子态结构无关，计算与实测电导率有差异，强调区分外在物理几何与内在电子态对扭曲材料性质贡献的必要性。
AI中文摘要：
扭曲双层石墨烯中的旋光性可作为层间电子相干性的标志。在时间反演对称双层系统中，即使没有层间耦合也可能出现旋光性。这种旋光性源于与系统物理几何相关的外在几何结构，与电子态结构无关。首先通过一维导线的纯经典双层阵列说明该效应，接着研究扭曲双层石墨烯，发现其旋光性完全归因于层间相干。在此过程中观察到，在Bistritzer-MacDonald框架中计算的电导率与实验室框架中可测量的电导率有显著差异。最后考虑扭曲双层MoTe2，先是作为旋光性恰好消失的原始模型，然后是有弱应变和位移场的情况，表明几何旋光性可主导相干旋光性。研究结果凸显了区分外在物理几何和内在电子态对扭曲材料性质贡献的必要性。
英文摘要：
Gyrotropy in twisted bilayer graphene can be used as a signature of interlayer electronic coupling. Gyrotropy can emerge in the absence of interlayer coupling in time-reversal symmetric bilayer systems. This gyrotropy originates from the extrinsic geometry associated with the physical geometry of the system and is independent of the structure of the electronic states. We first illustrate this effect for a purely classical bilayer array of one-dimensional wires. Next we study pristine twisted bilayer graphene and show that the gyrotropy is entirely due to interlayer coupling. Finally we consider twisted bilayer MoTe2, first as a pristine model where the gyrotropy exactly vanishes, and then with weak strain and displacement fields where we show that the geometric gyrotropy can dominate the gyrotropy due to interlayer coupling. Our results call attention to the necessity to separate the contribution of extrinsic physical geometry from the contribution of intrinsic electronic states to the properties of twisted materials.
