Protected gap closing in Josephson junctions constructed on Bi$_2$Te$_3$ surface

TL;DR

This paper provides experimental evidence of gap closing and full transparency in Josephson junctions on Bi$_2$Te$_3$, supporting the potential of topological insulator surfaces for hosting Majorana zero modes.

Contribution

It demonstrates direct experimental evidence of gap closing and full transparency in Josephson junctions on Bi$_2$Te$_3$, highlighting the surface's suitability for Majorana zero modes.

Findings

Evidence of gap closing in Bi$_2$Te$_3$ Josephson junctions

Observation of full transparency in electron transport

Bi$_2$Te$_3$ surface as a platform for Majorana modes

Abstract

On the road of searching for Majorana zero modes (MZMs) in topological insulator-based Josephson junctions, a highly-sought signature is the protected full transparency of electron transport through the junctions due to the existence of the MZMs, associated with complete gap closing between the electron-like and hole-like Andreev bound states (ABSs). Here, we present direct experimental evidence of gap closing and full transparency in single Josephson junctions constructed on the surface of three-dimensional topological insulator (3D TI) Bi$_2$Te$_3$. Our results demonstrate that the 2D surface of 3D TIs provides a promising platform for hosting and manipulating MZMs.