Low Energy Electrodynamics of a Superconducting Epitaxial Bismuth/Nickel Bilayer

ORAL

Abstract

Epitaxial Bi film grown on thin Ni film has strong spin-orbit coupling and no inversion symmetry. Recent results show that this Bi/Ni bilayer has superconductivity that breaks time-reversal symmetry (TRS). It is believed to be a candidate to realize a 2D topological superconductor. We investigate superconductivity in this interesting and unusual 2D bilayer system using time domain THz transmission spectroscopy (TDTS). Superconductivity is exhibited below 4.1K, which is surprising as it is known that in isolation both ferromagnetic Ni and rhombohedral Bi films are not superconducting. We study the frequency response of the complex conductivity of the bilayer. A superconducting gap structure with an energy scale close to the weak coupling s-wave BCS value is clearly seen. High-precision THz polarimetry provides additional information about time-reversal symmetry breaking in this compound.

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Presenters

  • Prashant Chauhan

    Department of Physics and Astronomy, The Johns Hopkins University

Authors

  • Prashant Chauhan

    Department of Physics and Astronomy, The Johns Hopkins University

  • Fahad Mahmood

    Department of Physics and Astronomy, The Johns Hopkins University, Johns Hopkins University, Johns Hopkins Univ

  • Di Yue

    Department of Physics, Fudan University

  • Peng-Chao Xu

    Department of Physics, Fudan University

  • Xiaofeng Jin

    Department of Physics, Fudan University

  • Peter Armitage

    Department of Physics and Astronomy, The Johns Hopkins University, Department of Physics and Astronomy, Johns Hopkins Unversity, Johns Hopkins University, Johns Hopkins Univ, Institute for Quantum Matter, Johns Hopkins University, The Johns Hopkins University