High magnetic field stability in a planar graphene-NbSe2 SQUID

Abstract Thin NbSe2 retains superconductivity at high in-plane magnetic field up to 30 T. In this work we construct an atomically thin, all van der Waals SQUID, in which current flows between NbSe2 contacts through two parallel graphene weak links. This fully planar device remains uniquely stable at high in-plane field. This enables tracing the evolution of the critical current interference patterns as a function of the field up to 4.5 T, allowing nm-scale sensitivity to deviations from a perfect atomic plane. We present numerical methods to retrieve asymmetric current distributions J0(x) from measured interference maps, and suggest a new application of the dual junction geometry to probe the current density in the absence of phase information. The interference maps exhibit a striking field-driven transition, indicating a redistribution of supercurrents to narrow channels. Our results suggest the existence of a preferred conductance channel with an exceptional stability to in-plane magnetic field.