Josephson junctions of Weyl semimetal $\text{WTe}_2$ induced by spontaneous nucleation of $\text{PdTe}$ superconductor

TL;DR

This paper demonstrates a novel method to create Josephson junctions with Weyl semimetal WTe2 by inducing superconductivity through spontaneous PdTe formation, enabling topological superconductor interfaces.

Contribution

The study introduces a simple annealing process to form superconducting PdTe in WTe2/Pd contacts, facilitating Josephson junction fabrication with topological semimetals.

Findings

Spontaneous PdTe formation enables Josephson junctions in WTe2.

Low-temperature annealing prevents superconductivity, high-temperature induces it.

The technique simplifies creating topological superconductor interfaces.

Abstract

We report on the fabrication of Josephson junction devices with weak links utilizing the Weyl and higher-order topological semimetal $\text{WTe}_2$. We show that $\text{WTe}_2\text{/Pd}$ contact annealed at a low temperature of 80{\deg}C did not exhibit superconducting properties because neither $\text{WTe}_2$ nor Pd are superconductors in the ground state. Upon 180{\deg}C annealing, spontaneous formation of superconducting $\text{PdTe}$ due to Pd diffusion enabled us to obtain the interface between $\text{WTe}_2$ and superconductor suitable for the Josephson junction. This result is a facile technique to make a Josephson junction and induce Cooper pairs into topological telluride semimetals.