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The rising of intrinsic magnetic topological insulators MnBi2Te4/(Bi2Te3)n

Date: 2020-11-06
Time: 10:00
Venue: M253
Speaker: 刘奇航?副教授

南方科技大学物理系

Abstract:

The rising of topological materials MnBi2Te4/(Bi2Te3)n with built-in magnetization provides a great platform for the realization of both Chern-insulator and axion-insulator phases, manifesting integer and half-integer quantum anomalous Hall (QAH) effects, respectively [1-3]. Using both model Hamiltonian and first-principles calculations, we demonstrate that rich 2D and 3D topological phase diagrams can be established with the mapping of MnBi2Te4/(Bi2Te3)n systems. For the 2D topological phases, we provide design principles to trigger integer QAH states by tuning experimentally accessible knobs, such as slab thickness and magnetization [2]. For the 3D topological phases, we find that the surface anomalous Hall conductivity in the axion-insulator phase is a well-localized hanging around e2/2h, depending on the magnetic homogeneity [3]. We then discuss the preconditions and several experimental proposals to reveal the surface anomalous Hall effect in MnBi2Te4/(Bi2Te3)n. Finally, some experimental progresses and theoretical insights on the issue of the surface gaps in MnBi2Te4/(Bi2Te3)n is discussed (if time permits) [4-7].

References

[1] C. Hu et al. Nat. Commun. 11, 97 (2020).

[2] H. Sun et al. Phys. Rev. Lett. 123, 096401 (2019).

[3] M. Gu et al. arXiv:2005.13943 (2020).

[4] Y. Hao et al. Phys. Rev. X 9, 041038 (2019).

[5] X. Wu et al. Phys. Rev. X 10, 031013 (2020).

[6] X. Ma et al. arXiv:2004.09123 (2020).

[7] R. Lu et al. arXiv:2009.04140 (2020).

报告人简介

刘奇航,南方科技大学副教授,本科及博士毕业于北京大学物理学院,曾任美国西北大学博士后、美国科罗拉多大学博尔德分校助理研究员;主要从事以密度泛函理论为主的凝聚态理论研究,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、拓扑等物性,以及功能导向的新型材料设计及预测。工作期间以主要作者身份已发表包括Nat. Phys.、Nat. Commun.、Phys. Rev. X、Phys, Rev. Lett.、Nano Lett.、JACS等多篇学术论文;署名作者共计已发表学术论文60余篇,Google Scholar统计引用超过3700次;2018年入选“国家特聘青年专家”。

邀请人:刘恩克(82649247,ekliu@iphy.ac.cn)