Proximity induced superconductivity by Bi in topological $Bi_2Te_2Se$ and $Bi_2Se_3$ films: Evidence for a robust zero energy bound state possibly due to Majorana Fermions

TL;DR

This study demonstrates proximity-induced superconductivity in topological Bi2Te2Se and Bi2Se3 films, revealing zero bias conductance peaks and potential Majorana Fermions, advancing understanding of topological superconductivity.

Contribution

It provides experimental evidence of proximity-induced superconductivity and zero energy bound states in topological insulator films, suggesting possible Majorana Fermions.

Findings

Observation of superconductivity below 2-3 K in the films

Detection of a robust zero bias conductance peak

Evidence supporting Majorana Fermions in the system

Abstract

Point contact conductance measurements on topological $Bi_2Te_2Se$ and $Bi_2Se_3$ films reveal a signature of superconductivity below 2-3 K. In particular, critical current dips and a robust zero bias conductance peak are observed. The latter suggests the presence of zero energy bound states which could be assigned to Majorana Fermions in an unconventional topological superconductor. We attribute these novel observations to proximity induced local superconductivity in the films by small amounts of superconducting Bi inclusions or segregation to the surface, and provide supportive evidence for these effects.