Spin-orbit-enhanced robustness of supercurrent in graphene/WS$_2$ Josephson junctions

TL;DR

This study shows that strong spin-orbit interactions in graphene/WS2 Josephson junctions significantly enhance the supercurrent's robustness against high magnetic fields, especially in longer junctions, due to quasi-ballistic edge states.

Contribution

It demonstrates that proximity-induced spin-orbit interactions in graphene/WS2 junctions improve supercurrent resilience under high magnetic fields, revealing a new way to stabilize superconductivity.

Findings

Supercurrent persists up to 1 T in short junctions for both systems.

In longer junctions, only graphene on WS2 maintains superconductivity features up to 7 T.

Strong spin-orbit interactions induce quasi-ballistic edge states that enhance supercurrent robustness.

Abstract

We demonstrate enhanced robustness of the supercurrent through graphene-based Josephson junctions in which strong spin-orbit interactions (SOIs) are induced. We compare the persistence of a supercurrent at high magnetic fields between Josephson junctions with graphene on hexagonal boron-nitride and graphene on WS$_2$, where strong SOIs are induced via the proximity effect. We find that in the shortest junctions both systems display signatures of induced superconductivity, characterized by a suppressed differential resistance at a low current, in magnetic fields up to 1 T. In longer junctions however, only graphene on WS$_2$ exhibits induced superconductivity features in such high magnetic fields, and they even persist up to 7 T. We argue that these robust superconducting signatures arise from quasi-ballistic edge states stabilized by the strong SOIs induced in graphene by WS$_2$.