Effective medium theory for disordered two-dimensional graphene

TL;DR

This paper develops an effective medium theory to analyze electrical transport in disordered graphene, incorporating non-linear screening and exchange-correlation effects, and accurately describes conductivity across different doping regimes.

Contribution

It introduces a comprehensive effective medium theory that accounts for Coulomb interactions and exchange effects in disordered graphene, improving understanding of conductivity behavior.

Findings

Conductivity at the Dirac point is significantly influenced by exchange-correlation effects.

The theory accurately models the crossover from fluctuation-dominated to high doping regimes.

Quantitative agreement with experimental observations of conductivity variations.

Abstract

We develop an Effective Medium Theory to study the electrical transport properties of disordered graphene. The theory includes non-linear screening and exchange-correlation effects allowing us to consider experimentally relevant strengths of the Coulomb interaction. Assuming random Coulomb impurities, we calculate the electrical conductivity as a function of gate voltage describing quantitatively the full cross-over from the fluctuations dominated regime around the Dirac point to the large doping regime at high gate voltages. We find that the conductivity at the Dirac point is strongly affected by exchange correlation effects.