Proximity-induced Superconductivity in Epitaxial Topological Insulator/Iron Chalcogenide Heterostructure

ORAL

Abstract

Introducing superconductivity in the surface states of a topological insulator gives rise to exotic physics known as topological superconductivity. Surprisingly it was shown recently that superconductivity can arise at the interface of MBE-grown Bi2Te3/FeTe. In this work, we study whether this interfacial superconductivity can then proximitize the surface states of 8QL Bi2Te3/FeTe using four-terminal transport and transport tunneling spectroscopy. We fabricated lithography-free van der Waals tunnel junctions using AFM-etched graphite electrodes, thin hBN as a tunnel barrier, and dry transfer techniques to make the device inside a glovebox [Li, Cequn, et al. "Proximity-induced superconductivity in epitaxial topological insulator/graphene/gallium heterostructures." Nature Materials 22.5 (2023): 570-575]. Hall bar devices are also made on the same film. Transport studies show a superconducting transition temperature Tc~ 13K and a large critical field above 9T. Transport tunneling spectroscopy allows us to probe the density of states of the Bi2Te3/FeTe film. We observed a V-shaped dip in the differential conductance around zero bias with coherence peaks centered around 1.2 meV. These features weaken with increasing temperature and disappear around 13 K. We associate the tunneling spectra with a proximity-induced gap on the surface.

*Penn State MRSEC for Nanoscale Science (DMR-2011839)

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Presenters

  • Monalisa Yadav

    • The Pennsylvania State University

Authors

  • Monalisa Yadav

    • The Pennsylvania State University

  • Hemian Yi

    • Pennsylvania State University

  • Cequn Li

    • Pennsylvania State University

  • Kenji Watanabe

    • National Institute for Materials Science
    • NIMS
    • Research Center for Electronic and Optical Materials, National Institute for Materials Science
    • Research Center for Functional Materials, National Institute for Materials Science, 1-1 Namiki, Tsukuba 305-0044, Japan
    • National Institute for Material Science

  • Takashi Taniguchi

    • Kyoto Univ
    • National Institute for Materials Science
    • Research Center for Materials Nanoarchitectonics
    • Research Center for Materials Nanoarchitectonics, National Institute for Materials Science
    • National Institute for Materials Sciences
    • NIMS
    • International Center for Materials Nanoarchitectonics, National Institute for Materials Science, 1-1 Namiki, Tsukuba 305-0044, Japan
    • National Institute for Material Science
    • International Center for Materials Nanoarchitectonics, NIMS, Japan
    • International Center for Materials Nanoarchitectonics, Tsukuba
    • National Institue for Materials Science
    • Kyoto University
    • National Institute of Materials Science
    • International Center for Materials Nanoarchitectonics and National Institute for Materials Science

  • Cui-Zu Chang

    • Pennsylvania State University
    • The Pennsylvania State University

  • Jun Zhu

    • Pennsylvania State University