Search for topological superconductivity in the proximitized, quantum-spin-Hall edge state of bismuth bilayers

ORAL

Abstract

Two-dimensional topological insulators host helical, one-dimensional (1D) modes that are protected by time-reversal symmetry. Proximity induced superconductivity on such edge modes is predicted to be topological in nature and provide a platform for realization of Majorana zero modes. Previously, scanning tunneling microscopy (STM) studies have found evidence for the presence of topological edge modes in bismuth (Bi) bilayers on the surface of bulk Bi(111) [1]. By epitaxially growing thin films on the surface of Nb, we have successfully induced superconductivity into (111) oriented Bi films and bilayers . Using high-resolution STM spectroscopy and quasi-particle interference mapping, we characterize the nature of both the normal and the superconducting properties of Bi bilayer edge modes. We find the 1D edge mode to develop a hard superconducting gap that appears to be spectroscopically distinct from the gap of the 2D surface state of the bilayer islands. We will describe these and other experiments designed to elucidate the nature of superconductivity and search for signatures of topological superconductivity developing in these 1D topological edge states.

[1] I. Drozdov et al., Nature Phys. 10, 664–669 (2014)

–

Presenters

  • Berthold Jaeck

    Physics Department, Princeton University

Authors

  • Berthold Jaeck

    Physics Department, Princeton University

  • Yonglong Xie

    Physics department, Princeton Univ, Physics Department, Princeton University

  • Sangjun Jeon

    Physics department, Princeton Univ, Physics Department, Princeton University

  • Aris Alexandradinata

    Yale University, Physics Department, Yale University, Department of Physics, Yale University

  • Andrei Bernevig

    Physics Department, Princeton University, Department of Physics, Princeton University, Physics Department, Princeton Univ, Physics, Princeton University, Princeton University, Physics, Princeton

  • Ali Yazdani

    Physics department, Princeton Univ, Joseph Henry Laboratories & Department of Physics, Princeton University, Physics Department, Princeton University, Physics, Princeton University, Princeton University