Topological superconductivity and Majorana zero mode

发布时间:2018-06-21发布部门:理学院

主题:   Topological superconductivity and Majorana zero mode主讲人:   徐刚地点:   松江校区2号学院楼454会议室时间:   2018-07-06 13:30:00组织单位:   理学院

主讲人简介:徐刚,教授,博士生导师,第十三批“青年千人”计划。2010年于中科院物理所获博士学位,2010-2012年中科院物理所助理研究员,2012—2016年美国斯坦福大学访问学者,2017年至今在华中科技大学国家脉冲强磁场中心工作。主要从事关联电子体系与非常规超导、拓扑物质态、新型二维功能材料的第一性原理计算研究,发表论文36篇,其中PRL8篇,Nat.Nanotech.两篇,Nat. Phys.和Nat. commun.各一篇,Nano letters两篇;两篇EPL论文入选“2008年中国百篇最具影响国际学术论文”,总引用4500多次。成功预言了铁基超导母体材料中的条纹状反铁磁基态——铁基超导获得国家自然科学一等奖的代表性工作之一。把凝聚态中电子态按照拓扑分类的概念从绝缘体推广到了半金属,首次提出双外尔半金属的概念,开启了Weyl费米子的研究热潮。

内容摘要:As one of the simplest systems for realizing Majorana fermions, the topological superconductor (TSC) playsan important role in both condensed matter physics and quantum computations. In this talk, I will introduce some basic concepts and experimental scheme of TSC.Then two specific proposals will be expatiated. (1)In half metal (with compatibleSOC)/s-wave superconductor heterostructures, our calculations show that azigzag edge of the monolayer MX2 terminated by metal atom M has edgestates with strong spin-orbit coupling and spontaneous magnetization. By proximity coupling with a superconducting substrate, TSC can be induced at suchedge. We propose NbS2 as a natural choice of substrate, and predictthat Majorana zero modes (MZMs) can be detected at the 120 degree corner. (2) In the‘superconducting topological metals’, we show that the three-dimensional extended s-wave Fe-based superconductors such as FeSe0.5Te0.5 have a metallic topologically nontrivial band structure, and exhibit anormal-topological-normal superconductivity phase transition on the (001)surface by tuning the bulk carrier doping level. In the TSC phase, a MZM is trapped at the end of a magnetic vortex line. We further show that the surface TSC phase only exists up to a certain bulk pairing gap. These results pave aneffective way to realize the TSC and Majorana fermions in a large class of superconductors.

报告主持:梁拥成 教授

视频:   摄影: 撰写:梁拥成  信息员:唐晓亮  编辑:段然

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