Bulk-boundary correspondence in higher-order topological superconductors

报告人

Assoc. Prof. Xiaoyu Zhu (朱小宇)

Xi’an Jiaotong University

时间

2024年4月24日（星期三）下午2：30

地点

物质科学教研楼B902会议室

朱小宇，西安交通大学物理学院副教授。2011年和2016年在南京大学分别取得学士和博士学位，期间以联合培养身份到加拿大英属哥伦比亚大学访问交流，之后入职西安交通大学。主要从事凝聚态物理中拓扑物态的理论研究，近年来比较关注高阶拓扑体系。

报告摘要

Higher-order topological superconductors are characterized by Majorana modes localized at corners or hinges.  Topological phase transitions in these higher-order phases can be driven by variations in a bulk parameter without closing the bulk gap. This presents a challenge in establishing a direct bulk-boundary correspondence, as conventional bulk invariants change only upon the closure of the bulk gap. In this talk, I will introduce our recent studies of two-dimensional higher-order topological superconductors in D, DIII and BDI symmetry classes. We demonstrate that in certain phases, a pair of topological invariants that are derived from Fermi level crossings can be used to characterize higher-order topology. These invariants may change with the closure of either bulk or edge gaps, thereby providing a clear demonstration of bulk-boundary correspondence in these higher-order phases.

References：

[1] Hong Wang and Xiaoyu Zhu, PRB 108, 125426 (2023).