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Crystal and magnetic structure of magnetic topological insulators MnBi<sub>2n</sub>Te<sub>3n+1</sub>

ORAL

Abstract

We present a systematic investigation of the crystal structure and magnetism of van der Waals topological insulators MnBi2nTe3n+1 (n = 1, 2) using single-crystal neutron diffraction, where emergent quantum phenomena have been recently observed. We show unambiguously that MnBi2Te4 orders antiferromagnetically below 24 K featured by a magnetic symmetry RI-3c while MnBi4Te7 is antiferromagnetic below 13 K with a distinct magnetic space group Pc-3c1. They both present antiferromagnetically coupled ferromagnetic layers with spins along the c-axis. Further, we put forward a stacking rule for the crystal structure of an infinitely adaptive series MnBi2nTe3n+1 with the building unit of [Bi2Te3]. This enables us to draw that a two-dimensional magnetism limit might be realized in the derivatives. Our work may promote the theoretical predictions of exotic quantum states in the series of MnBi2nTe3n+1.

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Presenters

  • LEI DING

    Oak Ridge National Lab, Neutron Scattering Division, Oak Ridge National Laboratory

Authors

  • LEI DING

    Oak Ridge National Lab, Neutron Scattering Division, Oak Ridge National Laboratory

  • Chaowei Hu

    Physics, University of California, Los Angeles, Physics and Astronomy, UCLA, Physics and Astronomy, Univerisity of California, Los Angeles, University of California, Los Angeles, Department of Physics and Astronomy and California NanoSystems Institute, University of California, Department of Physics and Astronomy and California Nano Systems Institute, University of California, Los Angeles, CA 90095, USA, University of California Los Angeles

  • Feng Ye

    Neutron Scattering Division, Oak Ridge National Laboratory, Oak Ridge National Lab

  • Erxi Feng

    Neutron Scattering Division, Oak Ridge National Laboratory, Oak Ridge National Lab

  • Ni Ni

    Univ of California Los Angeles, Physics, University of California, Los Angeles, Physics and Astronomy, UCLA, Department of Physics and Astronomy, University of California Los Angeles, University of California, Los Angeles, Department of Physics and Astronomy and California NanoSystems Institute, University of California, Department of Physics and Astronomy and California Nano Systems Institute, University of California, Los Angeles, CA 90095, USA, University of California Los Angeles, Department of Physics and Astronomy, University of California, Los Angeles

  • Huibo Cao

    Oak Ridge National Lab, Oak Ridge National Laboratory, Neutron Scattering Division, Oak Ridge National Laboratory, Oak Ridge, TN 37831, USA, Neutron Scattering Division, Oak Ridge National Laboratory, Neutron Scattering Division, Oak Ridge National Laboratory, Oak Ridge, Tennessee 37831, USA, Oak Ridge Natl Lab