Many-body orbital paramagnetism in doped graphene sheets

TL;DR

This paper demonstrates that many-body effects induce a finite, positive orbital magnetic susceptibility in doped graphene, which is otherwise zero in noninteracting massless Dirac fermions away from the Dirac point.

Contribution

The study provides an exact calculation of the first-order Coulomb interaction correction to the orbital magnetic susceptibility in doped graphene.

Findings

OMS is zero for noninteracting fermions away from the Dirac point

Coulomb interactions make OMS finite and positive

Doped graphene's OMS is dominated by many-body effects

Abstract

The orbital magnetic susceptibility (OMS) of a gas of noninteracting massless Dirac fermions is zero when the Fermi energy is away from the Dirac point. Making use of diagrammatic perturbation theory, we calculate exactly the OMS of massless Dirac fermions to first order in the Coulomb interaction demonstrating that it is finite and positive. Doped graphene sheets are thus unique systems in which the OMS is completely controlled by many-body effects.