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物理学院“博约学术论坛”系列报告(第160期)

发布日期:2018年09月08日
题目:Efficient Topological Materials Discovery Using Symmetry Indicators

报告人:万贤纲 教授(南京大学 物理学院)

时  间:2018年9月10日(周一)上午9:30

地  点:新葡萄京娱乐场8455中心教学楼610

摘要:Topological materials (TMs) showcase intriguing physical properties defying expectations based on conventional materials, and hold promise for the development of devices with new functionalities. While several theoretically proposed TMs have been experimentally confirmed, extensive experimental exploration of topological properties as well as applications in realistic devices have been held back due to the lack of excellent TMs in which interference from trivial Fermi surface states is minimized. Here, we integrate the recently established theory of symmetry indicators of band topology into first-principle band-structure calculations, and test it on a databases of previously synthesized crystals. The combined algorithm is found to efficiently unearth topological materials and predict topological properties like protected surface states. By applying our method 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.

简历:万贤纲简介:南京大学理学学士(1994年),南京大学理学博士(2000年)。南京大学物理系讲师(2001—2003),南京大学物理系副教授(2003—2009),南京大学物理系教授(2010—)(其中2003年10月至2005年1月日本国立材料研究所博士后 2005年6月至2007年美国加州大学戴维斯分校访问),“国家杰出青年科学基金”获得者(2015)以及“长江学者”(2016)。提出了新型拓扑量子态—Weyl 半金属,引发了国际上Weyl半金属的研究热潮;发展了一套计算磁性相互作用的方法并确定多个复杂体系的基态磁构型;预言了Axion 绝缘体;预言了倒空间局域电声子耦合能诱导出奇宇称配对超导体;预言新型BiS2层状超导体的超导机制源于近电荷密度波不稳。

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