Novel self-epitaxy for inducing superconductivity in the topological insulator (Bi1-xSbx)2Te3

TL;DR

This paper reports a novel self-epitaxy method where Pd deposition on (Bi$_{1-x}$Sb$_x$)$_2$Te$_3$ induces a superconducting PdTe$_2$ layer, enabling efficient proximity-induced superconductivity in topological insulators for device applications.

Contribution

The study introduces a simple self-epitaxy technique to form a superconducting PdTe$_2$ layer on topological insulators, facilitating superconductivity without complex epitaxial growth processes.

Findings

Pd deposition induces PdTe$_2$ formation with Tc ~1 K.

Proximity effect confirmed by supercurrent in Josephson devices.

Method enables fabrication of TI-based superconducting nanodevices.

Abstract

Using the superconducting proximity effect for engineering a topological superconducting state in a topological insulator (TI) is a promising route to realize Majorana fermions. However, epitaxial growth of a superconductor on the TI surface to achieve a good proximity effect has been a challenge. We discovered that simply depositing Pd on thin films of the TI material (Bi$_{1-x}$Sb$_x$)$_2$Te$_3$ leads to an epitaxial self-formation of PdTe$_2$ superconductor having the superconducting transition temperature of ~1 K. This self-formed superconductor proximitizes the TI, which is confirmed by the appearance of a supercurrent in Josephson-junction devices made on (Bi$_{1-x}$Sb$_x$)$_2$Te$_3$. This self-epitaxy phenomenon can be conveniently used for fabricating TI-based superconducting nanodevices to address the superconducting proximity effect in TIs.