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Competing magnetic interactions in MnBi<sub>4</sub>Te<sub>7</sub>

ORAL

Abstract

Intrinsic magnetic topological insulators (TIs) MnBi2nTe3n+1 provides a promising material platform to realize exotic topological quantum states such as high temperature quantum anomalous Hall insulator and axion insulator. Besides non-trivial band topology, magnetism is another necessary ingredient to realize these quantum states[1-5]. In this talk, we will show a ferromagnetic (FM) phase with TC~14 K can be realized with a small concentration substitution of Sb for Bi in Mn(Bi,Sb)4Te7. We have also observed strong competition between interlayer FM and antiferromagnetic (AFM) coupling. In pristine MnBi4Te7, we observed an AFM transition at 13.1 K, followed by a FM transition at 8.9 K, consistent with previous reports[6]. However, in a 60%Sb doped sample, we find a FM phase switches to an AFM phase at ~4.4K. These complex magnetic transitions offer rich opportunities to observe how the topological phases evolve with magnetism. We will also discuss the origin of the AFM and FM competition in this material system.
1.Zhang et al.,PRL,122,206401(2019)
2.Li et al.,Sci. Adv.5,eaaw5685(2019)
3.Otrokov et al.,Nature 576,416(2019)
4.Hu et al.,Nat. Commun.11,97(2020)
5.Yan et al.,PRM 4,054202(2020)
6.Vidal et al.,PRX 9,041065(2019)

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Presenters

  • Yingdong Guan

    Pennsylvania State University, Physics, The Pennsylvania State University

Authors

  • Yingdong Guan

    Pennsylvania State University, Physics, The Pennsylvania State University

  • Wei Ning

    Pennsylvania State University

  • Seng Huat Lee

    Pennsylvania State University, Department of Physics, Pennsylvania State University, Physics, The Pennsylvania State University, 2D Crystal Consortium, Materials Research Institute, Penn State University, Materials Research Institute, Pennsylvania State University

  • Zhiqiang Mao

    Pennsylvania State University, Department of Physics, Penn State University, The Pennsylvania State University, Penn State University, Physics, Penn State University, Department of Physics, Pennsylvania State University, Department of Physics, The Pennsylvania State University, Physics, The Pennsylvania State University, Physics, Pennsylvania State University, Department of Materials Science and Engineering, Pennsylvania State University