报告题目：Towards ideal topological materials: Comprehensive database searches using symmetry indicators

报 告 人：万贤纲，南京大学物理学院教授

报告时间：2019-03-14 16:00

报告地点：理科楼郑裕彤讲堂

报告摘要：Although the richness of spatial symmetries has led to a rapidly expanding inventory of possible topological crystalline (TC) phases of electrons, physical realizations have been slow to materialize due to the practical difficulty to ascertaining band topology in realistic calculations. Here, we integrate the recently established theory of symmetry indicators of band topology into first-principle band-structure calculations and apply it to all non-magnetic compounds in the 230 space groups. An exhaustive database search reveals thousands of TM candidates. Of these, we highlight the excellent TMs, the 258 topological insulators and 165 topological crystalline insulators which have either noticeable full band gap or a considerable direct gap together with small trivial Fermi pockets. We also give a list of 489 topological semimetals with the band crossing points located near the Fermi level. All predictions obtained through standard generalized gradient approximation (GGA) calculations were cross-checked with the modified Becke-Johnson (MBJ) potential calculations, appropriate for narrow gap materials. With the electronic and optical behavior around the Fermi level dominated by the topologically non-trivial bands, these newly found TMs candidates open wide possibilities for realizing the promise of TMs in next-generation electronic devices.

[1] Efficient Topological Materials Discovery Using Symmetry Indicators Feng Tang, Hoi Chun Po, Ashvin Vishwanath, Xiangang Wan* Nature Physics (2019) DOI:10.1038/s41567-019-0418-7

[2] Comprehensive search for topological materials using symmetry indicators Feng Tang, Hoi Chun Po, Ashvin Vishwanath, Xiangang Wan* Nature 566, 486 (2019).

[3] Efficient Topological Materials Discovery Using Symmetry Indicators Feng Tang, Hoi Chun Po, Ashvin Vishwanath, Xiangang Wan* Science Advances (in press)