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建校70周年文峰云论坛——数理基础与前沿研究论坛:Intrinsic magnetic topological insulators: MnBi2Te4 and beyond

发布部门:理学院   发布人:江莎   发布时间:2020年05月10日 12:11

dnfsf www.okaluge.com 报告题目: Intrinsic magnetic topological insulators: MnBi2Te4 and beyond

报告人: 勇助理教授(华大学物理系,青年千人)

报告时间:2020514日(星期)下午 14:30-16:00

报告方式腾讯会议平台

链接直接加入会议:https://meeting.tencent.com/s/5ziWq4h8ce1b

会议 ID618 212 856,会议密码:0514

报告摘要:

    Intrinsic magnetic topological insulators are novel states of quantum matter possessing both inherent magnetic order and topological electronic states, which offer a fertile playground to explore emergent quantum physics. The antiferromagnetic topological insulator MnBi2Te4 [1-4] is a rapidly rising star in the research field. The material is theoretically predicted to host rich topological quantum states (e.g., topological axion states, magnetic Weyl semimetal, and quantum anomalous Hall (QAH) effect). In addition to theoretical proposals, I will also introduce recent experimental findings, including the discoveries of antiferromagnetic topological insulator states [1,4], QAH effect [5], robust axion insulator and Chern insulator phases [6], high-Chern-number and high-temperature QAH effect [7], helical Chern insulator phase [8], etc. An outlook for future work will be given. Importantly, the working temperature of MnBi2Te4 is limited by its rather weak ferromagnetic exchange, making superior material candidates desirable. In this perspective, I will briefly report an unexpected theoretical finding of room-temperature ferromagnetism and large-gap QAH insulators in lithium-decorated iron-based superconductor materials LiFeX (X=S, Se, Te) [9], which is awaiting for experimental proof.

Reference:

[1] Y. Gong, et al. Chin. Phys. Lett. 36, 076801 (2019).

[2] J. Li, et al. Sci. Adv. 5, eaaw5685 (2019).

[3] D. Zhang, et al. Phys. Rev. Lett. 122, 206401 (2019).

[4] M. M. Otrokov, et al. Nature 576, 416 (2019).

[5] Y. Deng, et al. Science, eaax8156 (2020).

[6] C. Liu, et al. Nature Mater. 19, 522 (2020).

[7] J. Ge, et al. arXiv:1907.09947.

[8] C. Liu, et al. arXiv:2001.08401.

[9] Y. Li, et al. arXiv:1912.07461.

 

报告人简介:

Dr. Yong Xu is now an associate professor at Department of Physics, Tsinghua University (2018-present) and a unit leader of at RIKEN Center for Emergent Matter Science (CEMS) (2015-present). He received his B.S. degree in Physics (2005) and Ph.D. degree in Condensed Matter Physics (2010) at Tsinghua University. Then he worked at Fritz Haber Institute of Max Planck Society (2011-2013) and Stanford University (2013-2015) as a postdoc and a research scholar, respectively.

His main research interest is to understand/predict unusual quantum phenomena and novel material properties, based on first-principles density functional theory calculations. He has published over 70 SCI papers, including 20 papers in top journals (Science、Science Adv.、Nature Mater.、Nature Phys.、Nature Nanotech.、PRL/PRX), with ~4000 times citations. His group predicted various novel quantum matter/states, including two-dimensional topological insulators stanene-related materials, type-II Ising superconductors, intrinsic magnetic topological insulator MnBi2Te4-family materials, topological thermoelectric effects, topological phonon states, etc. Many of the theoretical proposals have been successfully confirmed by experiments. He was awarded Alexander von Humboldt Fellowship of Germany, National Thousand Young Talents Program of China, and Young Faculty Award of Tsinghua University.

 

 

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                                                      重庆邮电大学理学院

                                                                              2020.5.10