题 目：Edge conduction and gate induced superconductivity in monolayer WTe₂

报告人：费再瑶 博士后

                 华盛顿大学

时 间：2018年5月9日下午3:00

地 点：国家脉冲强磁场科学中心C204

报告摘要：

Topology and correlation are two essential concepts in modern condensed matter physics. They give rise to a lot of interesting phenomena and exotic ground states, among which the quantum spin Hall (QSH) effect and superconductivity are two famous examples. Monolayer WTe₂, a topological nontrivial semimetal in the bulk form, has recently been predicted to be a QSH insulator if a bulk gap opens. In experiment, we find that at temperatures below about 100 K a gap appears and the 2D bulk becomes insulating near zero doping, while the edges remain conducting. At lower temperatures, the edge conduction is strongly suppressed by in-plane magnetic field. Most of the observations are consistent with monolayer WTe₂being a quantum spin Hall insulator. Surprisingly, when the monolayer is electrostatically doped away from the insulating state, the 2D bulk turns superconducting below about 1 K. Bilayer and trilayer WTe₂, on the other hand, do not show any signature of edge conduction or superconductivity. Monolayer WTe₂thus provides a unique platform for studying different electronic ground states and the interplay among them.

报告人简介：

2011年毕业于中国科学技术大学物理系，同年进入美国华盛顿大学（西雅图），于2017年获凝聚态物理博士学位。博士期间，师从David Cobden教授从事一维二氧化钒（VO₂）纳米线、二维石墨烯（Graphene）、二维碲化钨（WTe₂）等纳米材料的光学以及输运性质的研究。博士毕业至今，在华盛顿大学许晓栋教授组继续从事凝聚态物理博士后研究。他以第一作者身份在Nature Physics上发表论文1篇，在Nature上接收论文1篇，同时有多篇合作论文正在Science和Nature Materials上审稿中。

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