High-Temperature Andreev Tunneling in the Surface States of a Topological Insulator

ORAL

Abstract

Topological insulators (TIs) are materials with high spin-orbit coupling that possess conductive helical surface states. In order to study the exotic properties of the TI surface states, it is favorable to work with TIs that have a low bulk conductivity and exhibit insulating behavior. Bi2Te2Se has been confirmed to have a high bulk resistivity, and it still shows Shubnikov-de Haas oscillations originating from the two-dimensional surface states. We report the observation of coherent Andreev tunneling into the surface states of Bi2Te2Se in high-temperature superconductor (Bi2Sr2CaCu2O8$+\delta)$/Bi2Te2Se junctions fabricated by mechanical bonding method. The differential conductance measurements will be presented in various temperatures and magnetic fields. The characterization of the zero-bias conductance peak observed, suggests that we are tunneling into the surface states of the TI rather than the bulk states.

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Authors

  • Parisa Zareapour

    Department of Physics and Institute for Optical Sciences, University of Toronto

  • Alex Hayat

    University of Toronto, Department of Physics and Institute for Optical Sciences, University of Toronto

  • Shu Yang Frank Zhao

    Department of Physics and Institute for Optical Sciences, University of Toronto

  • Michael Kreshchuk

    Department of Physics and Institute for Optical Sciences, University of Toronto

  • Achint Jain

    Department of Physics and Institute for Optical Sciences, University of Toronto

  • Zhijun Xu

    Brookhaven National Laboratory, CMP\&MS Department, Brookhaven National Laboratory, Brookhaven National Lab

  • Alina Yang

    CMP\&MS Department, Brookhaven National Laboratory, Brookhaven National Laboratory

  • Genda Gu

    Brookhaven National Laboratory, CMP\&MS Department, Brookhaven National Laboratory, Condensed Matter Physics \& Materials Science Department, Brookhaven National Laboratory, Brookhaven National Laboratory, Upton, NY, Brookhaven National Laboratory, Condensed Matter Physics \& Materials Science Department, NY 11973, Brookheaven National Laboratory

  • Shuang Jia

    Department of Chemistry, Princeton University

  • Robert Cava

    Department of Chemistry, Princeton University, Dept. Chem. Princeton University, New Jersey 08544, Princeton University, Department of Chemistry, Princeton University, Princeton, NJ 08544, USA

  • Kenneth S. Burch

    Department of Physics and Institute for Optical Sciences, University of Toronto, University of Toronto, Department of Physics, University of Toronto