Magneto-Transport Study of Magnetic/Nonmagnetic Topological Insulator Heterostructures

ORAL

Abstract

Breaking time-reversal symmetry in a topological insulator (TI) by a magnetic perturbation can give rise to a variety of exotic quantum phenomena such as quantum anomalous Hall effect. Since the surface states of TIs have a spin helical massless Dirac structure, undoped TI films usually show weak antilocalization (WAL) quantum corrections to diffusive transport, characterized by a positive magnetoresistance (MR). Here, we fabricate magnetically doped TI films on pristine TI films with different thicknesses to form magnetic/nonmagnetic TI heterostructures and systematically study their magneto-transport properties. When the thickness of the TI layer is ≤2QL, the MR shows a typical butterfly shape due to domain wall scattering. However, when the thickness of the TI layer is ≥ 3QL, the MR is suppressed, similar to the WAL cusp, but near the magnetization reversal regime. We speculate that this “dip” in MR near the coercive field is a result of the coexistence of the gapless surface state of the TI layer and the ferromagnetic order in the magnetic TI layer. Our study provides new insights into magneto-transport phenomena in the presence of a superposition of gapped and gapless surface states.

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Presenters

  • Di Xiao

    Physics, Penn State University, Physics, The Pennsylvania State University, Department of Physics, The Pennsylvania State University, Pennsylvania State University, Department of Physics, Pennsylvania State University

Authors

  • Di Xiao

    Physics, Penn State University, Physics, The Pennsylvania State University, Department of Physics, The Pennsylvania State University, Pennsylvania State University, Department of Physics, Pennsylvania State University

  • Fei Wang

    Department of Physics, Pennsylvania State University, Physics, The Pennsylvania State University, Department of Physics, The Pennsylvania State University

  • Run Xiao

    Physics, Penn State University, Physics, The Pennsylvania State University, Department of Physics, Pennsylvania State University, Physics, Pennsylvania State University

  • Ling Zhang

    Physics, Penn State University, Department of Physics, Pennsylvania State University, Physics, The Pennsylvania State University, Department of Physics, The Pennsylvania State University, Pennsylvania State University

  • Haizhou Lu

    Physics, Southern University of Science and Technology, Department of Physics, Southern University of Science and Technology

  • Chao-Xing Liu

    Pennsylvania State University, Physics, The Pennsylvania State University, Department of Physics, The Pennsylvania State University, Department of Physics, Pennsylvania State University

  • Moses H. W. Chan

    Department of Physics, Pennsylvania State University, Physics, The Pennsylvania State University, Department of Physics, The Pennsylvania State University, Pennsylvania State University

  • Cui-Zu Chang

    Pennsylvania State University, Physics, Penn State University, Department of Physics, Pennsylvania State University, Physics, The Pennsylvania State University, Department of Physics, The Pennsylvania State University

  • Nitin Samarth

    Department of Physics and Materials Research Institute, Pennsylvania State University, Physics, Penn State University, Physics, The Pennsylvania State University, Pennsylvania State University, Department of Physics, Pennsylvania State University, Materials Research Institute, Pennsylvania State University, Department of Physics, The Pennsylvania State University, Physics, Pennsylvania State University