Low energy theory of disordered graphene

TL;DR

This paper investigates the low-energy transport properties of disordered graphene, revealing mechanisms that protect its conductivity against localization effects, especially at low doping levels.

Contribution

It combines mean field and bosonization methods to analyze how disorder and doping influence graphene's transport, highlighting a potential suppression of localization.

Findings

Disordered graphene exhibits universal conductance near the quantum limit.

At low doping, conductivity is protected by renormalization mechanisms.

Strong localization may be suppressed even at very low temperatures.

Abstract

At low values of external doping graphene displays a wealth of unconventional transport properties. Perhaps most strikingly, it supports a robust 'metallic' regime, with universal conductance of the order of the conductance quantum. We here apply a combination of mean field and bosonization methods to explore the large scale transport properties of the system. We find that, irrespective of the doping level, disordered graphene is subject to common mechanisms of Anderson localization. However, at low doping a number of renormalization mechanisms conspire to protect the conductivity of the system, to an extend that strong localization may not be seen even at temperatures much smaller than those underlying present experimental work.