Proximity-induced superconductivity in graphene

TL;DR

This paper proposes inducing superconductivity in graphene by placing superconductive islands on it, resulting in a small energy gap and complex magnetic field-dependent phase transitions.

Contribution

It introduces a novel method to achieve superconductivity in graphene via proximity effect with superconductive islands and analyzes the resulting phase behavior.

Findings

Critical temperature T_c can reach several Kelvins.

A small energy gap E_g appears at low temperatures due to proximity effect.

Magnetic fields can destroy the spectral gap, leading to a superconductive glass state.

Abstract

We propose a way of making graphene superconductive by putting on it small superconductive islands which cover a tiny fraction of graphene area. We show that the critical temperature, T_c, can reach several Kelvins at the experimentally accessible range of parameters. At low temperatures, T<<T_c, and zero magnetic field, the density of states is characterized by a small gap E_g<T_c resulting from the collective proximity effect. Transverse magnetic field H_g(T) E_g is expected to destroy the spectral gap driving graphene layer to a kind of a superconductive glass state. Melting of the glass state into a metal occurs at a higher field H_{g2}(T).