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

报告人: 万贤纲   南京大学

报告时间：12月11日 下午 14:00-15:00

报告地点：物理科技楼101

报告邀请人： 江华

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.

Feng Tang, Hoi Chun Po, Ashvin Vishwanath, Xiangang Wan, arXiv:1805.07314 (2018).

Feng Tang, Hoi Chun Po, Ashvin Vishwanath, Xiangang Wan, arXiv:1806.04128 (2018).

Feng Tang, Hoi Chun Po, Ashvin Vishwanath, Xiangang Wan, arXiv:1807.09744 (2018).

报告人简介：万贤纲，南京大学物理学院教授，博士生导师。1990-2000在南京大学获得学士、硕士、博士学位。主要采用第一性原理和有效模型相结合的手段研究具有强自旋轨道耦合的关联电子体系。近年来在拓扑材料领域的一系列原创性工作受到了同行的广泛关注。关于Weyl半金属的工作被Science的前瞻文章评价为“(凝聚态领域)一个新的前沿”, 获得2014年度香港大学Daniel Tsui(崔琦)Fellowship，2015年国家杰出青年科学基金，2016年入选长江学者计划。

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