Superconductivity in type-II Weyl-semimetal WTe2 induced by a normal metal contact

TL;DR

This paper reports the induction of superconductivity at the interface between WTe2, a topologically rich Weyl-semimetal, and palladium, revealing potential for topological superconductivity and insights into its physical parameters.

Contribution

It demonstrates superconductivity in WTe2 via a normal metal contact and characterizes its properties, suggesting a possible flat-band origin and non-trivial superconducting state.

Findings

Superconductivity with Tc ~1.2 K observed at WTe2/Pd interface.

Superconducting parameters indicate low Fermi velocity and high density of states.

Critical in-plane magnetic field exceeds Pauli limit, implying non-trivial superconductivity.

Abstract

WTe$_2$ is a material with rich topological properties: it is a 2D topological insulator as a monolayer and a Weyl-semimetal and higher-order topological insulator (HOTI) in the bulk form. Inducing superconductivity in topological materials is a way to obtain topological superconductivity, which lays at the foundation for many proposals of fault tolerant quantum computing. Here, we demonstrate the emergence of superconductivity at the interface between WTe$_2$ and the normal metal palladium. The superconductivity has a critical temperature of about 1.2 K. By studying the superconductivity in perpendicular magnetic field, we obtain the coherence length and the London penetration depth. These parameters correspond to a low Fermi velocity and a high density of states at the Fermi level. This hints to a possible origin of superconductivity due to the formation of flat bands. Furthermore, the critical in-plane magnetic field exceeds the Pauli limit, suggesting a non-trivial nature of the superconducting state.