Josephson effect in graphene SBS junctions

TL;DR

This paper investigates the Josephson effect in graphene superconductor-barrier-superconductor junctions, revealing oscillatory behavior of the Josephson current as a function of barrier width and gate voltage, with implications for experimental realization.

Contribution

It introduces the analysis of Josephson current oscillations in graphene junctions as functions of barrier parameters and explains the phenomenon in the thin barrier limit.

Findings

Josephson current oscillates with barrier width and gate voltage.

Oscillations explained by transmission resonance of Dirac quasiparticles.

Relevance for experimental graphene-based superconducting devices.

Abstract

We study Josephson effect in graphene superconductor- barrier- superconductor junctions with short and wide barriers of thickness $d$ and width $L$, which can be created by applying a gate voltage $V_0$ across the barrier region. We show that Josephson current in such graphene junctions, in complete contrast to their conventional counterparts, is an oscillatory function of both the barrier width $d$ and the applied gate voltage $V_0$. We also demonstrate that in the thin barrier limit, where $V_0 \to \infty$ and $d \to 0$ keeping $V_0 d$ finite, such an oscillatory behavior can be understood in terms of transmission resonance of Dirac-Bogoliubov-de Gennes quasiparticles in superconducting graphene. We discuss experimental relevance of our work.