Effect of Coulomb interactions on the physical observables of graphene

TL;DR

This paper reviews how electron-electron Coulomb interactions influence the electronic properties of neutral graphene, focusing on renormalization effects, the potential for gap opening, and the role of Fermi velocity as a key parameter.

Contribution

It updates previous theoretical results on Coulomb interactions in graphene, incorporating recent experimental data to refine understanding of Fermi velocity renormalization and interaction effects.

Findings

Fermi velocity is the main parameter affecting graphene's electronic properties.

Coulomb interactions significantly renormalize the Fermi velocity.

No conclusive evidence for a low-energy gap opening in neutral graphene.

Abstract

We give an update of the situation concerning the effect of electron-electron interactions on the physics of a neutral graphene system at low energies. We revise old renormalization group results and the use of 1/N expansion to address questions of the possible opening of a low-energy gap, and the magnitude of the graphene fine structure constant. We emphasize the role of Fermi velocity as the only free parameter determining the transport and electronic properties of the graphene system and revise its renormalization by Coulomb interactions in the light of recent experimental evidence.