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南方大学刘启航副教授讲座通知
发布人:王燚  发布时间:2019-08-25   浏览次数:10

应物理学院李伟奇副教授邀请,南方科技大学刘奇航研究员将于827日对物理学院进行访问,访问期间将举行学术报告并进行交流,欢迎各位感兴趣的师生参加。

题目:磁性拓扑绝缘体的反常量子霍尔效应

时间827日上午10:00

地点:理学楼308

摘要As one of paradigmatic phenomena in condensed matter physics, the quantum anomalous Hall effect (QAHE) in stoichiometricChern insulators has drawn great interest for years. Recently, MnBi2Te4 thin films manifests the QAH effect at a record high temperature of 4.5 K in the forced ferromagnetic state above 10 Tesla. By realizing a bulk MnBi4Te7 with alternating [MnBi2Te4]and [Bi2Te3] layers, we suggest that it is a Z2 antiferromagnetic topological insulator with a small out-of-plane saturation field of ~ 0.2 Tesla. Using model Hamiltonian analysis and first-principle calculations, we then establish a topological phase diagram and map on it with different two-dimensional configurations, which is taken from the recently-grown magnetic topological insulators MnBi4Te7 and MnBi6Te10. These configurations manifest various topological phases, including quantum spin Hall effect with and without time-reversal symmetry, as well as QAHE. We then provide design principles to trigger QAHE by tuning experimentally accessible knobs, such as slab thickness and magnetization. Our work reveals that superlattice-like magnetic topological insulators with tunable exchange interaction serve as an ideal platform to realize the long-sought QAHE in pristine compounds.

报告人简介:刘奇航,南方科技大学物理系副教授,中组部2018年“国家特聘青年专家”入选者,主要从事以密度泛函理论为主的凝聚态理论研究,聚焦真实材料。研究兴趣包括理解材料中新奇的电学,磁学,光学,缺陷,自旋极化,拓扑等性质及它们的耦合,以及功能导向的新型材料设计及预测。刘奇航博士以第一作者或通讯作者身份已发表包括Nature. PhysicsNature. CommunicationsPhysical.Review. XPhysical. Review. LettersNano LettersAdvanced. Functional. Materials.等多篇学术论文;署名作者共计已发表学术论文40余篇,Google Scholar统计引用超过2900次;担任Physical. Review. LettersNano LettersAdvanced. Materials等期刊审稿人。