学术报告（3月24日）

主持人：姚道新 教授

欢迎广大师生踊跃参加！

报告内容：Topological insulators (TIs) belong to a new phase of matter with their topological nature protected by time reversal symmetry. Of particular interest is that they can provide a novel platform, where their surface states usually play an essential role, to generate new topological phases, such as quantum anomalous Hall (QAH) effect after breaking time-reversal symmetry. In this talk, however, we will propose a new scenario to realize QAH phase even in topologically trivial phase without surface states involved. Specifically in a candidate material, TlBi(S1-xSex)2, we will demonstrate that the QAH phases with different Chern numbers can be achieved by means of tuning the exchange field strength or the sample thickness. Our scenario successfully reduces the necessary exchange coupling strength for a high Chern number, as long as the material gets close to the topological phase transition point, compared to the old scenario. Furthermore, we find that a given Chern number can also be tuned by a perpendicular electric field, which naturally occurs when a substrate is present.

报告人简介：蔡维枫博士（台湾beat365中国唯一官方网站 & 新加坡国立大学），国家青年海外高层次人才项目入选者，美国加州大学洛杉矶分校UCLA获得博士学位（2008），台湾大学获得硕士学位（2002）和学士学位（1998），曾在美国普渡大学和日本东京大学做博士后研究。