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Surface magnetism of antiferromagnetic topological insulator MnBi<sub>2</sub>Te<sub>4</sub>

ORAL

Abstract

MnBi2Te4 is a promising candidate of antiferromagnetic (AFM) topological insulator which might host fascinating quantized anomalous Hall effect or axion insulator state in few molecular layers1,2. These quantum phenomena are induced by the mass gap on Dirac surface states opened by the A-type AFM order (alternating ferromagnetic layers)3 with uniaxial anisotropy in MnBi2Te4. However, recent high resolution angle resolved photoemission spectroscopy studies reveal gapless surface states, indicating paramagnetic or non-uniaxial A-type AFM orders4–7. Yet there is no direct evidence of such surface magnetism. Recently we demonstrated magnetic imaging of AFM domain walls in MnBi2Te4 family using our homemade cryogenic magnetic force microscope (MFM)8. In this talk, we will present MFM studies of MnBi2Te4 single crystals to address the nature of surface magnetism.

References
1. Otrokov, M. M. et al. PRL 122, 107202 (2019).
2. Gong, Y. et al. CPL 36, 076801 (2019).
3. Yan, J.-Q. et al. PRM 3, 064202 (2019).
4. Li, H. et al. arXiv:1907.06491 (2019).
5. Swatek, P. et al. arXiv:1907.09596 (2019).
6. Hao, Y.-J. et al. arXiv:1907.03722 (2019).
7. Chen, Y. J. et al. arXiv:1907.05119 (2019).
8. Sass, P. M. et al. arXiv:1910.06488 (2019).

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Presenters

  • Weida Wu

    Physics and Astronomy, Rutgers University, New Brunswick, Department of Physics and Astronomy, Rutgers University, Department of Physics and Astronomy, Rutgers, The State University of New Jersey, Department of Physics and Astronomy, Rutgers University, New Brunswick, Rutgers University, New Brunswick

Authors

  • Weida Wu

    Physics and Astronomy, Rutgers University, New Brunswick, Department of Physics and Astronomy, Rutgers University, Department of Physics and Astronomy, Rutgers, The State University of New Jersey, Department of Physics and Astronomy, Rutgers University, New Brunswick, Rutgers University, New Brunswick

  • Paul Sass

    Physics and Astronomy, Rutgers University, New Brunswick, Department of Physics and Astronomy, Rutgers University, Rutgers University, New Brunswick

  • Jiaqiang Yan

    Materials Science and Engineering, The University of Tennessee, Oak Ridge National Lab, Oak Ridge National Laboratory, Materials Science and Technology Division, Oak Ridge National Laboratory, Materials Science and Technology Division, Oak Ridge National Lab, Oak Ridge National Laboratory, Oak Ridge, TN 37831, USA