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Nonlinear Hall effect in topological insulator-ferromagnet heterostructures

ORAL

Abstract

Topological insulators (TIs) are a new class of materials which have insulating bulk bands and gapless helical surface states. The unique spin-momentum locking property leads to large charge-to-spin conversion efficiency which can be used to manipulate the magnetization in an adjacent ferromagnetic layer via spin-orbit torques (SOTs). However, more rich phenomena can happen in topological insulator/ferromagnet bilayers. Here, we report current-nonlinear Hall effect in Bi2Se3/CoFeB heterostructures measured by second harmonic Hall voltage method, which is commonly used to extract SOTs in TI/FM bilayers. By field dependence analysis and magneto-optical Kerr effect spin-orbit torque measurement, the origin of the second harmonic Hall voltage is mainly attributed to asymmetric magnon scattering mechanism. We further show that the second harmonic Hall resistance might be linked to quantum interference effect in TIs.

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Presenters

  • Yang Wang

    University of Delaware, Physics and Astronomy, University of Delaware

Authors

  • Yang Wang

    University of Delaware, Physics and Astronomy, University of Delaware

  • Yong Wang

    University of Delaware

  • Tao Wang

    University of Delaware, Physics and Astronomy, University of Delaware

  • Yu-Sheng Ou

    University of Delaware

  • Yi Ji

    University of Delaware

  • Matthew F Doty

    University of Delaware, Department of Materials Science and Engineering, University of Delaware

  • Branislav Nikolic

    University of Delaware, Univ of Delaware, Department of Physics & Astronomy, University of Delaware, Department of Physics and Astronomy, University of Delaware, USA

  • Stephanie Ann Law

    University of Delaware

  • John Q Xiao

    University of Delaware, Physics and Astronomy, University of Delaware