中国物理B ›› 2023, Vol. 32 ›› Issue (8): 87802-087802.doi: 10.1088/1674-1056/acd68a

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Magneto-optical Kerr and Faraday effects in bilayer antiferromagnetic insulators

Wan-Qing Zhu(朱婉情) and Wen-Yu Shan(单文语)   

  1. Department of Physics, School of Physics and Materials Science, Guangzhou University, Guangzhou 510006, China
  • 收稿日期:2023-03-27 修回日期:2023-05-10 接受日期:2023-05-18 发布日期:2023-07-24
  • 通讯作者: Wen-Yu Shan E-mail:wyshan@gzhu.edu.cn
  • 基金资助:
    Project supported by the National Natural Science Foundation of China (Grant No.11904062), the Starting Research Fund from Guangzhou University (Grant No.RQ2020076), and Guangzhou Basic Research Program, jointed funded by Guangzhou University (Grant No.202201020186).

Magneto-optical Kerr and Faraday effects in bilayer antiferromagnetic insulators

Wan-Qing Zhu(朱婉情) and Wen-Yu Shan(单文语)   

  1. Department of Physics, School of Physics and Materials Science, Guangzhou University, Guangzhou 510006, China
  • Received:2023-03-27 Revised:2023-05-10 Accepted:2023-05-18 Published:2023-07-24
  • Contact: Wen-Yu Shan E-mail:wyshan@gzhu.edu.cn
  • Supported by:
    Project supported by the National Natural Science Foundation of China (Grant No.11904062), the Starting Research Fund from Guangzhou University (Grant No.RQ2020076), and Guangzhou Basic Research Program, jointed funded by Guangzhou University (Grant No.202201020186).

摘要: Control and detection of antiferromagnetic topological materials are challenging since the total magnetization vanishes. Here we investigate the magneto-optical Kerr and Faraday effects in bilayer antiferromagnetic insulator MnBi2Te4. We find that by breaking the combined mirror symmetries with either perpendicular electric field or external magnetic moment, Kerr and Faraday effects occur. Under perpendicular electric field, antiferromagnetic topological insulators (AFMTI) show sharp peaks at the interband transition threshold, whereas trivial insulators show small adjacent positive and negative peaks. Gate voltage and Fermi energy can be tuned to reveal the differences between AFMTI and trivial insulators. We find that AFMTI with large antiferromagnetic order can be proposed as a pure magneto-optical rotator due to sizable Kerr (Faraday) angles and vanishing ellipticity. Under external magnetic moment, AFMTI and trivial insulators are significantly different in the magnitude of Kerr and Faraday angles and ellipticity. For the qualitative behaviors, AFMTI shows distinct features of Kerr and Faraday angles when the spin configurations of the system change. These phenomena provide new possibilities to optically detect and manipulate the layered topological antiferromagnets.

关键词: magneto-optical Kerr and Faraday effects, antiferromagnetic topological insulators, bilayer systems

Abstract: Control and detection of antiferromagnetic topological materials are challenging since the total magnetization vanishes. Here we investigate the magneto-optical Kerr and Faraday effects in bilayer antiferromagnetic insulator MnBi2Te4. We find that by breaking the combined mirror symmetries with either perpendicular electric field or external magnetic moment, Kerr and Faraday effects occur. Under perpendicular electric field, antiferromagnetic topological insulators (AFMTI) show sharp peaks at the interband transition threshold, whereas trivial insulators show small adjacent positive and negative peaks. Gate voltage and Fermi energy can be tuned to reveal the differences between AFMTI and trivial insulators. We find that AFMTI with large antiferromagnetic order can be proposed as a pure magneto-optical rotator due to sizable Kerr (Faraday) angles and vanishing ellipticity. Under external magnetic moment, AFMTI and trivial insulators are significantly different in the magnitude of Kerr and Faraday angles and ellipticity. For the qualitative behaviors, AFMTI shows distinct features of Kerr and Faraday angles when the spin configurations of the system change. These phenomena provide new possibilities to optically detect and manipulate the layered topological antiferromagnets.

Key words: magneto-optical Kerr and Faraday effects, antiferromagnetic topological insulators, bilayer systems

中图分类号:  (Magneto-optical effects)

  • 78.20.Ls
75.50.Ee (Antiferromagnetics) 73.21.Ac (Multilayers)