Proximal Anomalous Hall Effect in Ferromagnetic Insulator/Bulk-insulating BiSbTeSe2 Heterostructures

ORAL

Abstract

Realization of Quantized Anomalous Hall Effect in topological insulators (TIs) thus far has been limited to ultra-thin MBE films of Cr- or V-doped (Bi,Sb)2Te3. In this system the disorder of the dopant landscape may limit the quantization temperature range in which the chiral channels can be observed. The alternative is to obtain proximal ferromagnetism in a 3D TI by creating a trilayer sandwich comprising ferromagnetic insulator (FMI) on the top and bottom surfaces of a TI. Here we report on the trilayer structure comprising bulk-insulating TI BiSbTeSe2 (BSTS) sandwiched between a two-dimensional van der Waals ferromagnetic insulator Cr2Ge2Te6 (CGT) grown using Bridgeman method. The structure was assembled in the inert-gas glovebox to prevent oxidation and contamination of the interface. h-BN capping was used to protect CGT against degradation in air. The out-of-plane magnetization of CGT down to thicknesses of 18 nm was confirmed by exfoliating it directly atop our custom-designed Hall microsensor chips. The enhancement of proximal magnetism obtained by (1) the optimal thickness of BSTS, (2) using pressure to obtain a better interfacial coupling, and (3) by electrostatic gating to the Dirac gap will be discussed.

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Presenters

  • Shihua Zhao

    City College of New York

Authors

  • Shihua Zhao

    City College of New York

  • Haiming Deng

    City College of New York

  • Daniel A Rhodes

    Columbia University, Physics, Columbia University, National High Magnetic Field Laboratory, Tallahassee, FL-32310, USA., Columbia Nano Initiative, Columbia University, Department of Mechanical Engineering, Columbia University, New York, NY 10027 USA, Mechanical Engineering, Columbia University, Columbia Univ

  • James Hone

    Columbia University, Mechanics, Columbia University, Department of Mechanical Engineering, Columbia University in the City of New York, Department of Mechanical Engineering, Columbia University, Department of Mechanical Engineering, Columbia University, New York, NY 10027 USA, Mechanical Engineering, Columbia University

  • Marcin Konczykowski

    Laboratoire des Solides Irradiés, École Polytechnique, F-91128 Palaiseau, France, Ecole Polytechnique, Ecole Polytechnique, Palaiseau, France, LSI, Ecole Polytechnique, Laboratoire des Solides Irradies, Ecole Polytechnique

  • Agnieszka Wolos

    University of Warsaw, Physics, University of Warsaw

  • Lia Krusin-Elbaum

    City College of New York