Kohn-Luttinger superconductivity in graphene

TL;DR

This paper explores how superconductivity can emerge in graphene near Van Hove singularities due to anisotropic electron-electron interactions, potentially leading to observable superconducting temperatures above 10 K.

Contribution

It demonstrates the mechanism of Kohn-Luttinger superconductivity in graphene and shows how tuning to Van Hove singularities can enhance critical temperatures.

Findings

Superconductivity arises from anisotropic electron scattering near Van Hove points.

The superconducting transition temperature can exceed 10 K.

The pairing instability is linked to the symmetry modes with nontrivial angular dependence.

Abstract

We investigate the development of superconductivity in graphene when the Fermi level becomes close to one of the Van Hove singularities of the electron system. The origin of the pairing instability lies in the strong anisotropy of the e-e scattering at the Van Hove filling, which leads to a channel with attractive coupling when making the projection of the BCS vertex on the symmetry modes with nontrivial angular dependence along the Fermi line. We show that the scale of the superconducting instability may be pushed up to temperatures larger than 10 K, depending on the ability to tune the system to the proximity of the Van Hove singularity.