Quantum Anomalous Hall Effect and Exchange Interaction between Magnetic Topological Insulator and Antiferromagnetic Insulator

ORAL

Abstract

Integration of a quantum anomalous Hall (QAH) insulator with a magnetically ordered material provides an additional degree of freedom to manipulate the magnetic orders and exotic quantum states. Here, we report molecular beam epitaxy (MBE) growth of high quality magnetically doped topological insulator (MTI) and the observation of QAH effect on an antiferromagnetic insulator Cr2O3. The exchange coupling between the two materials is investigated using field-cooling-dependent magnetometry and polarized neutron reflectometry. Exchange bias is observed when the sample is field-cooled under an out-of-plane magnetic field, and polarized neutron reflectometry reveals an exchange spring-like magnetic depth profile when the system is magnetized within the film plane. Both techniques show strong interfacial interaction between the antiferromagnetic order of the Cr2O3 and the magnetic topological insulator. The exchange interaction between MTI and adjacent antiferromagnetic insulators enables the effective manipulation of the magnetic and topological order in the topological insulator films.

*We acknowledge the funding support from Army Research Office Multidisciplinary University Research Initiative (MURI) program under contract W911NF-16-1-0472 and WN911NF-20-2-0166.

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Presenters

  • Peng Zhang

    • University of California, Los Angeles
    • Department of Electrical and Computer Engineering, University of California, Los Angeles

Authors

  • Peng Zhang

    • University of California, Los Angeles
    • Department of Electrical and Computer Engineering, University of California, Los Angeles

  • Lei Pan

    • University of California, Los Angeles

  • Alexander Grutter

    • National Institute of Standards and Technology
    • Center for Neutron Research, National Institute of Standards and Technology
    • NIST Center for Neutron Research, NIST
    • NIST Gaithersburg

  • Tomohiro Nozaki

    • National Institute of Advanced Industrial Science and Technology (AIST)

  • Scott Chambers

    • Pacific Northwest National Laboratory

  • Jing Xia

    • University of California Irvine
    • Department of Physics, University of California at Irvine

  • Kang-Lung Wang

    • Department of Electrical and Computer Engineering, University of California, Los Angeles
    • University of California, Los Angeles