Tight-binding study of bilayer graphene Josephson junctions

TL;DR

This study uses tight-binding simulations to analyze the Josephson effect in bilayer graphene junctions, revealing unique proximity effects and supercurrent control mechanisms related to doping, junction length, and symmetry breaking.

Contribution

It provides the first self-consistent analysis of Josephson junctions in bilayer graphene, highlighting differences from single-layer graphene and supercurrent switching capabilities.

Findings

Distinct proximity effects at the Dirac point.

Supercurrent suppression in long junctions.

Supercurrent switching via potential difference.

Abstract

Using highly efficient simulations of the tight-binding Bogoliubov-de Gennes model we solved self-consistently for the pair correlation and the Josephson current in a Superconducting-Bilayer graphene-Superconducting Josephson junction. Different doping levels for the non-superconducting link are considered in the short and long junction regime. Self-consistent results for the pair correlation and superconducting current resemble those reported previously for single layer graphene except in the Dirac point where remarkable differences in the proximity effect are found as well as a suppression of the superconducting current in long junction regime. Inversion symmetry is broken by considering a potential difference between the layers and we found that the supercurrent can be switched if junction length is larger than the Fermi length.