Josephson penetration depth in coplanar junctions based on 2D materials

TL;DR

This paper investigates the large Josephson penetration depth in coplanar junctions based on 2D materials, deriving a new expression and confirming it through simulations, which advances understanding of their fundamental physics and design.

Contribution

It introduces a new theoretical expression for the Josephson penetration depth specific to 2D material-based junctions and validates it with numerical simulations.

Findings

Large Josephson penetration depth enabled by unique geometry

Derived a new expression for λ_J in 2D material junctions

Validated the expression through numerical simulations

Abstract

Josephson junctions and SQUIDs with graphene or other 2D materials as the weak link between superconductors have become a hot topic of research in recent years, with respect to both fundamental physics and potential applications. We have previously reported ultra-wide Josephson junctions (up to 80 {\mu}m wide) based on CVD graphene where the critical current was found to be uniformly distributed in the direction perpendicular to the current. In this paper, we demonstrate that the unusually large Josephson penetration depth {\lambda}_J that this corresponds to is enabled by the unique geometric structure of Josephson junctions based on 2D materials. We derive a new expression for the Josephson penetration depth of such junctions and verify our assumptions by numerical simulations.