Graphene via large N I: Renormalization

TL;DR

This paper uses a large-N renormalization group approach to analyze how Coulomb interactions and disorder influence electron scattering and transport in graphene, highlighting the dominance of vector potential disorder at low energies.

Contribution

It introduces a controlled large-N RG analysis showing vector potential disorder as the main elastic scattering mechanism in graphene at low energies.

Findings

Vector potential disorder dominates at low energy scales.

Scaling predictions for conductivity and thermopower are provided.

Coulomb interactions significantly affect transport in suspended graphene.

Abstract

We analyze the competing effects of moderate to strong Coulomb electron-electron interactions and weak quenched disorder in graphene. Using a one-loop renormalization group calculation controlled within the large-N approximation, we demonstrate that, at successively lower energy (temperature or chemical potential) scales, a type of non-Abelian vector potential disorder always asserts itself as the dominant elastic scattering mechanism for generic short-ranged microscopic defect distributions. Vector potential disorder is tied to both elastic lattice deformations ("ripples") and topological lattice defects. We identify several well-defined scaling regimes, for which we provide scaling predictions for the electrical conductivity and thermopower, valid when the inelastic lifetime due to interactions exceeds the elastic lifetime due to disorder. Coulomb interaction effects should figure strongly into the physics of suspended graphene films, where rs > 1; we expect vector potential disorder to play an important role in the description of transport in such films.