物理系徐刚学术报告的通知(Physics Department Colloquium)

编辑:江丹 来源:物理学系 时间:2019年11月05日 访问次数:0  源地址

题目:Some exotic topological states in Magnetic groups

报告人:徐刚 华中科技大学国家脉冲强磁场科学中心

地点: 教十二—201

时间: 118日,周五,15:30-16:30



In Magnetic groups (MGs), the time reversal symmetry is broken, but its combinations with some crystalline symmetries, named as crystalline time reversal symmetry (CTRS), are preserved, and can protect the novel topological phase against the local perturbations without destroy the magnetic symmetries. In this talk, I will introduce two works on the exotic topological quantum states in magnetic groups. 1. Antiferromagnetic (AFM) Dirac semimetals (DSMs) realized in the interlayer AFM EuCd2As2. In this work, we generalize the concept of DSM to the magnetic space groups (MSGs), and define a new category of DSM in type IV MGs. Many exotic topological states, such as the triple point semimetal and the AFM topological insulator holding of the half-quantum Hall effect can be derived from such AFM DSMs by breaking certain symmetry, providing an ideal platform to study topological phase transitions. 2. New type of topological superconductor (TSC) phase in the 1-dimensional (1D) MGs. We find that the CTRS could enrich the classification of TSC. In the 1D system generated by  or  symmetry, such CTRS could lead to the BDI class of TSC with  topological invariant, rather than the conventional D- or DIII-class (Z2 invariant). More interestingly, the TSC phase in the MGs generated by  and  are totally beyond the Altland and Zirnbauer symmetry classes, but belong to a new type of  ( for  system) classification, in which the robust Majorana zero modes are protected by the unitary chiral symmetry. The minimal tight binding BdG Hamiltonians satisfying  or  MGs are also constructed to illustrate the novel TSC phase.



徐刚,华中科技大学教授,博士生导师,青年千人计划入选者。2010年获中国科学院物理研究所博士学位,2010-2012年任中科院物理所助理研究员,2012-2016在美国斯坦福大学做访问研究,20169月至今在华中科技大学国家脉冲强磁场中心工作。2017年入选中组部第十三批千人计划“青年项目”。2018年获科技部重点研发计划青年项目(项目负责人);获“2018年度中国科学院杰出科技成就奖(集体)”。主要从事新奇物性和材料的第一性原理计算和理论研究。研究兴趣包括:强关联与非常规超导、拓扑物质态,新型二维功能材料等,已发表学术论文40多篇,其中Nature子刊、PRL等国际顶级期刊17篇,另有两篇论文入选“2008年中国百篇最具影响国际学术论文”;总引用6000多次, H因子27