摘要

Topological semimetal, characterized by Weyl/Dirac nodes in the bulk and Fermi arcs on the surfaces, is a new state of three-dimensional (3D) quantum matters, different from the 3D topological insulators. Weyl nodes are stable topological objects, and can be viewed as effective magnetic monopoles in the 3D momentum space. Its time-reversal invariant version ---- 3D Dirac node, however, consists of two copies of distinct Weyl nodes with opposite chirality, and requires additional symmetry protection, such as the crystal symmetry. Novel properties, such as the giant diamagnetism and the linear quantum magnetoresistance can be expected for such semimetal states. In this talk, I will first present a general description of topological semimetal states, and then discuss its possible material realizations based on the first-principles calculations. We will show two theoretical predictions, Na3Bi and Cd3As2, where the 3D Dirac cones are experimentally observed recently.
References:
[1] G. Xu, H. M. Weng, Z. J. Wang, X. Dai, Z. Fang, PRL, 107, 186806 (2011).
[2] Z. J. Wang, Y. Sun, X. Q. Chen, C. Franchini, G. Xu, H. M. Weng, X. Dai, Z. Fang, PRB 85, 195320 (2012).
[3] Z. J. Wang, H. M. Weng, Q. S. Wu, X. Dai, Z. Fang, PRB 88, 125427 (2013).
[4] Z. K. Liu, B. Zhou, Y. Zhang, et.al., Science 343, 864 (2014).
[5] Z. K. Liu, J. Jiang, B. Zhou, Z. J. Wang, et.al., Nature Materials 13, 677 (2014).

报告人简介

中国科学院物理研究所研究员、博士生导师，美国物理学会会士（APS Fellow）。1996年获华中理工大学博士学位，1996-2003年访问日本、美国，2003年入选中科院“百人计划”回国到物理研究所工作至今。主要从事于计算凝聚态物理方面的研究，包括：（1）电子结构计算方法发展；（2）关联电子系统；（3）拓扑绝缘体；（4）材料计算预测与新奇量子现象研究。共发表SCI论文120余篇，他引8000余次。曾获2008年国际理论物理中心ICTP奖，2011年中国科学院杰出科技成就奖，2011年求是杰出科技成就集体奖，2012年全球华人物理学会“亚洲成就奖”，2013年周培源物理奖，2013年国家自然科学一等奖，2014周光召基础科学奖。

邀请人：贾金锋 jfjia@sjtu.edu.cn

联系人：杨洋 catherinecherry@sjtu.edu.cn