High Magnetic Field Stability in a Planar Graphene-NbSe<sub>2</sub> SQUID.

Zalic, Ayelet; Taniguchi, Takashi; Watanabe, Kenji; Gazit, Snir; Steinberg, Hadar · Nano Lett · 2023

basic_science · Level V

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Abstract

Thin NbSe<sub>2</sub> retains superconductivity at a high in-plane magnetic field up to 30 T. In this work we construct a novel atomically thin, all van der Waals SQUID, in which current flows between NbSe<sub>2</sub> contacts through two parallel graphene weak links. The 2D planar SQUID remains uniquely stable at high in-plane field, which enables tracing critical current interference patterns as a function of the field up to 4.5 T. From these we extract the evolution of the current distribution up to high fields, demonstrating sub-nanometer sensitivity to deviation of current flow from a perfect atomic plane and observing a field-driven transition in which supercurrent redistributes to a narrow channel. We further suggest a new application of the asymmetric SQUID geometry to directly probe the current density in the absence of phase information.