Fu Bo, Bai Kai-Zhi, Shen Shun-Qing
School of Sciences, Great Bay University, Dongguan, 523000, Guangdong Province, China.
Department of Physics, The University of Hong Kong, Pokfulam Road, Hong Kong, China.
Nat Commun. 2024 Aug 13;15(1):6939. doi: 10.1038/s41467-024-51215-x.
We predict a half-quantized mirror Hall effect induced by mirror symmetry in strong topological insulator films. These films are known to host a pair of gapless Dirac cones in the first Brillouin zone associated with surface electrons. Our findings reveal that mirror symmetry assigns a unique mirror parity to each Dirac cone, resulting in a half-quantized Hall conductance of for each cone. Despite the total electrical Hall conductance being null due to time-reversal invariance, the difference in the Hall conductance between the two cones yields a quantized Hall conductance of for the difference in mirror currents. The effect of helical edge mirror current - a crucial feature of this quantum effect - may, in principle, be determined by means of electrical measurements. The half-quantum mirror Hall effect reveals a type of mirror-symmetry induced quantum anomaly in a time-reversal invariant lattice system, giving rise to a topological metallic state of matter with time-reversal invariance.
我们预测，在强拓扑绝缘体薄膜中，镜面对称性会诱导出半量子化的镜像霍尔效应。已知这些薄膜在与表面电子相关的第一布里渊区中存在一对无隙狄拉克锥。我们的研究结果表明，镜面对称性为每个狄拉克锥赋予了独特的镜宇称，导致每个锥的霍尔电导为半量子化。尽管由于时间反演不变性，总的电霍尔电导为零，但两个锥之间的霍尔电导差异产生了镜像电流差异的量子化霍尔电导。螺旋边缘镜像电流的效应——这种量子效应的一个关键特征——原则上可以通过电学测量来确定。半量子镜像霍尔效应揭示了时间反演不变晶格系统中一种镜面对称性诱导的量子反常，从而产生了具有时间反演不变性的拓扑金属态物质。
