Neutron diffraction study of magnetism in van der Waals layered MnBi<sub>2n</sub>Te<sub>3n+1</sub>

ORAL

Abstract

We present a systematic investigation of the crystal structure and magnetism of MnBi2nTe3n+1 (n = 1, 2, 3, 4) which have been recently found to be intrinsic magnetic topological insulators. Neutron diffraction unveils that considerable Bi atoms occupy at the Mn sites while no detectable magnetic Mn occupies at non-magnetic sites in all the cases. The occupancy of Mn monotonically decreases with the increase of n. Polarized neutron diffraction on MnBi4Te7 reveals that its magnetization density is obviously accumulated at the Mn site, corroborating the distribution of the chemical defects. We suggest that the site defects but not site mixings are inherent and should be a common mark to this family. Our work provides material-specified structural parameters that may be useful for band structure calculations to understand the observed topological surface states and for designing quantum magnetic materials through chemical doping.

*The research was supported by the U.S. Department of Energy (DOE), Office of Science, Office of Basic Energy Sciences, Early Career Research Program Award KC0402010, under Contract DE-AC05-00OR22725 and Award Number DE-SC0011978. This research used resources at the High Flux Isotope Reactor, a DOE Office of Science User Facility operated by ORNL.

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Presenters

  • LEI DING

    • Oak Ridge National Lab
    • Oak Ridge National Laboratory

Authors

  • LEI DING

    • Oak Ridge National Lab
    • Oak Ridge National Laboratory

  • Chaowei Hu

    • University of California, Los Angeles
    • Physics, University of California, Los Angeles
    • Physics and Astronomy Department, University of California, Los Angeles
    • Department of Physics and Astronomy, University of California, Los Angeles

  • Erxi Feng

    • Oak Ridge National Laboratory

  • Miaofang Chi

    • Oak Ridge National Laboratory
    • Oak Ridge National Lab
    • Center for Nanophase Materials Sciences, Oak Ridge National Laboratory

  • Ni Ni

    • University of California, Los Angeles
    • Physics, University of California, Los Angeles
    • Physics and Astronomy Department, University of California, Los Angeles
    • Department of Physics and Astronomy, University of California, Los Angeles

  • Huibo Cao

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