Superconducting proximity effects and pairing in (Bi<sub>1-x</sub>Sb<sub>x</sub>)<sub>2</sub>Te<sub>3</sub> films on niobium

ORAL

Abstract

Interfacing a topological insulator (TI) with an s-wave superconductor (SC) can favor the formation of helical-Cooper pairing in the topological surface states. However, realizing this system is often challenging, due to the impracticality of growing TIs on most SCs and possibly defects and Fermi surface/lattice mismatch at the TI/SC interface. By developing a novel cleavage-based “flip chip” approach, we have successfully fabricated single-crystalline (Bi1-xSbx)2Te3 thin films of a predetermined thickness (3 – 10 quintuple layers) on top of bulk Nb film. Moreover, by carefully controlling the growth conditions of the prototypical TI Bi2Te3 films, we find from our angle-resolved photoemission spectroscopy (ARPES) measurements of Bi2Te3/Nb that the Fermi level can lie in the band gap, giving rise to a lightly n-doped TI on a SC substrate. Ongoing laser ARPES and STM measurements would clarify the mechanism of coupling between the SC and the topological surface states in these doped TI/SC thin-film heterostructures. Our study underlines methods for realizing superconductivity in TIs and for clarifying the pairing in these heterostructures for applications in topological quantum computing.

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Presenters

  • Joseph Hlevyack

    • University of Illinois at Urbana-Champaign
    • Department of Physics, University of Illinois-Urbana-Champaign

Authors

  • Joseph Hlevyack

    • University of Illinois at Urbana-Champaign
    • Department of Physics, University of Illinois-Urbana-Champaign

  • Yang Bai

    • University of Illinois at Urbana-Champaign
    • Physics, University of Illinois at Urbana-Champaign
    • Department of Physics, University of Illinois-Urbana-Champaign

  • Meng-Kai Lin

    • Department of Physics, University of Illinois Urbana-Champaign
    • University of Illinois at Urbana-Champaign
    • Physics, University of Illinois at Urbana-Champaign
    • Department of Physics, University of Illinois-Urbana-Champaign

  • Peng Chen

    • Physics, University of Illinois at Urbana-Champaign
    • Department of Physics, University of Illinois-Urbana-Champaign

  • David Flötotto

    • University of Illinois at Urbana-Champaign
    • Department of Physics, University of Illinois-Urbana-Champaign

  • Ro-Ya Liu

    • University of Illinois at Urbana-Champaign
    • Institute of Physics, Academia Sinica
    • Department of Physics, University of Illinois-Urbana-Champaign

  • Akihiro Tsuzuki

    • Institute for Solid State Physics, The University of Tokyo

  • Kozo Okazaki

    • Institute for Solid State Physics, University of Tokyo
    • Institute for Solid State Physics, The University of Tokyo

  • Shik Shin

    • Institute for Solid State Physics, the University of Tokyo, Japan
    • Institute for Solid State Physics, University of Tokyo
    • Institute for Solid State Physics, The University of Tokyo

  • James N Eckstein

    • Univ of Illinois - Urbana
    • Department of Physics, University of Illinois-Urbana-Champaign

  • Tai-Chang Chiang

    • University of Illinois at Urbana-Champaign
    • Physics, University of Illinois
    • Department of Physics, University of Illinois Urbana-Champaign
    • Physics, University of Illinois at Urbana-Champaign
    • Department of Physics, University of Illinois-Urbana-Champaign
    • Physics, University of Illinois Urbana-Champaign