报告题目：Observation of Z-class Higher-Order Topological Phases

报告人： 梅锋 教授（山西大学）

报告时间：2023年06月02日（星期五）15：30-17：00

报告地点：腾讯会议ID：368-4368-9521

报告摘要：

Topological corner states are exotic topological boundary states that are bounded to zero-dimensional geometry even the dimension of bulk systems is large than one. So far, all previous realizations of HOTIs are hallmarked by Z_2-class topological invariants and therefore have only one corner state at each corner. Here we report an experimental demonstration of Z-class HOTI phases in electric circuits, characterized by multiple chiral numbers N, hosting large-number corner modes at each corner. By measuring the impedance spectra and distributions, we clearly observe the multiple corner modes featured by Z-class HOTI phases. Moreover, we reveal that the local density of states (LDOS) at each corner are equally distributed at N corner unit cells, prominently differing from the Z_2-class case where the LDOS only dominates over one corner unit cell, allowing us to probe the topological number N. Our results extend the observation of HOTIs from Z_2 class to Z class and the coexistence of spatially overlapped large number of corner modes which may enable exotic topological devices that require high degeneracy boundary states.

报告人简介：

梅锋，教授，博士生导师，山西省“三晋学者”青年优秀人才。2012年6月华南师范大学和新加坡国立大学联合培养博士。2012年8月-2016年9月，先后在美国加州大学莫塞德分校、新加坡国立大学和中山大学博士后和副研究员。2016年11月进入山西大学量子光学与光量子器件国家重点实验室。近年来主要从事人工拓扑物态理论和实验研究，以第一作者和通信作者在Physical Review Letters 和 Light Science Applications 上发表多篇论文。

参考文献：

[1] Yi Li, Jia-Hui Zhang, Feng Mei*, Biye Xie*, Ming-Hui Lu*, Jie Ma*, Liantuan Xiao and Suotang Jia, arXiv:2305.10585 (2023).