Observation of Interface Superconductivity in a SnSe2-Epitaxial Graphene van der Waals Heterostructure

TL;DR

This study demonstrates the existence of interface superconductivity in a SnSe2-graphene heterostructure, revealing a conventional fully gapped superconductor driven by a two-dimensional electron gas at the interface.

Contribution

It provides direct experimental evidence of interface superconductivity in a van der Waals heterostructure and elucidates its mechanism involving a 2D electron gas.

Findings

Superconductivity observed in SnSe2-graphene heterostructure.

Superconducting gap characterized as fully gapped and conventional.

Vortices confirmed under magnetic field indicating superconducting state.

Abstract

We report on the direct observation of interface superconductivity in single-unit-cell SnSe2 films grown on graphitized SiC(0001) substrate by means of van der Waals epitaxy. Tunneling spectrum in the superconducting state reveals rather conventional character with a fully gapped order parameter. The occurrence of superconductivity is further confirmed by the presence of vortices under external magnetic field. Through interface engineering, we unravel the mechanism of superconductivity that originates from a two-dimensional electron gas formed at the interface of SnSe2 and graphene. Our finding opens up novel strategies to hunt for and understand interface superconductivity based on van der Waals heterostructures.