Probing magnetic orders in atomically thin Chern insulator MnBi<sub>2</sub>Te<sub>4</sub>

ORAL

Abstract

MnBi2Te4 is an emergent material platform for exploring topological phenomena owing to its intrinsic magnetic order combined with nontrivial topology. Bulk crystal has an A-type antiferromagnetic (AFM) order below its Neel temperature, while the layer dependent magnetism of thin flakes remains largely unexplored. It is unclear how the bulk band structure changes when the magnetic states are tuned by an external field, which is crucial for understanding the topological phase transition in this system. In this work, we probe the intrinsic magnetism of atomically thin MnBi2Te4 samples by reflective magnetic circular dichroism (RMCD), and correlate their magnetic order with transport measurements. We show that in thin flake the remnant magnetization and critical spin-flop field exhibit even-odd layer number effects. For both even and odd layers, applying a magnetic field drives the layered AFM state into a canted AFM state, and finally a ferromagnetic (FM) state. The tuning of magnetic states corresponds to concurrent topological phase transitions with a Chern number from C=0 to C=-1.

*Research on topological properties of MnBi2Te4 is primarily supported by DOE BES DE-SC0019443. Magneto-optical spectroscopy measurement is partially supported by DOE BES DE-SC0018171.

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Presenters

  • Zhong Lin

    • Department of Physics, University of Washington, Seattle
    • Department of Physics, University of Washington

Authors

  • Zhong Lin

    • Department of Physics, University of Washington, Seattle
    • Department of Physics, University of Washington

  • Dmitry Ovchinnikov

    • Department of Physics, University of Washington
    • University of Washington

  • Xiong Huang

    • University of California, Riverside
    • Department of Physics and Astronomy, University of California, Riverside
    • University of California, Reverside

  • Zaiyao Fei

    • Department of Physics, University of Washington
    • University of Washington

  • Jiaqi Cai

    • Department of Physics, University of Washington
    • University of Washington

  • Tiancheng Song

    • Department of Physics, University of Washington
    • University of Washington

  • Minhao He

    • Department of Physics, University of Washington
    • University of Washington

  • Qianni Jiang

    • University of Washington
    • Department of Physics, University of Washington
    • Physics, University of Washington

  • Chong Wang

    • Department of Physics, Carnegie Mellon University
    • Physics, Carnegie Mellon University
    • Carnegie Mellon University
    • Carnegie Mellon Univ

  • Hao Li

    • School of Materials Science and engineering, Tsinghua University
    • Tsinghua University

  • Yayu Wang

    • Tsinghua University
    • Department of Physics, Tsinghua University

  • Yang Wu

    • Department of Mechanical Engineering, Tsinghua University
    • Tsinghua University

  • Di Xiao

    • Carnegie Mellon Univ
    • Carnegie Mellon University
    • Department of Physics, Carnegie Mellon University
    • Physics, Carnegie Mellon University

  • Jiun-Haw Chu

    • University of Washington
    • Department of Physics, University of Washington, Seattle
    • Department of Physics, University of Washington
    • Physics, University of Washington

  • Jiaqiang Yan

    • Materials Science and Technology Division, Oak Ridge National Lab
    • Oak Ridge National Laboratory
    • University of Tennessee
    • Oak Ridge National Lab
    • Materials Science and Technology Division, Oak Ridge National Laboratory
    • Materials Science and Technology, Oak Ridge National Laboratory
    • Oak Ridge National Laboratory, Materials Science and Technology Division

  • Cui-Zu Chang

    • Pennsylvania State University
    • Department of Physics, The Pennsylvania State University
    • Department of Physics, Pennsylvania State University
    • The Pennsylvania State University

  • Yongtao Cui

    • University of California, Riverside
    • Department of Physics and Astronomy, University of California, Riverside
    • University of California, Reverside

  • Xiaodong Xu

    • Physics, University of Washington
    • Department of Physics, University of Washington
    • University of Washington
    • Department of Physics, University of Washington, Seattle
    • University of Washington, Seattle