报告题目：Quantum Spin Hall Effect and Spin Bott Index in Quasicrystal Lattice

报 告 人：Huaqing Huang（黄华卿），University of Utah

报告时间：2018-08-21 10:00

报告地点：理科楼C109

报告摘要：Despite the rapid progresses in the field of quantum spin Hall (QSH) effect, most of the QSH systems studied up to now are based on crystalline materials. Here we propose that the QSH effect can be realized in quasicrystal lattices (QLs). We show that the electronic topology of aperiodic and amorphous insulators can be characterized by a spin Bott index Bs. The nontrivial QSH state in a QL is identified by a nonzero spin Bott index Bs = 1, associated with robust edge states and quantized conductance. We also map out a topological phase diagram in which the QSH state lies in between a normal insulator and a weak metal phase due to the unique wavefunctions of QLs. Our findings not only provide a better understanding of electronic properties of quasicrystals but also extend the search of QSH phase to aperiodic and amorphous materials that are experimentally feasible.