DC conductivity of graphene with disorder

TL;DR

This paper models disorder in graphene using a coherent-potential approximation and Lloyd model, revealing how temperature-dependent scattering influences conductivity and resistivity, highlighting multiple scattering mechanisms.

Contribution

It introduces a model incorporating a temperature-dependent disorder strength to explain graphene's transport properties, including the effects of thermally induced excitations.

Findings

Temperature dependence of minimum conductivity explained

Resistivity at high densities matches model predictions

Two main scattering contributions identified

Abstract

We model disorder in graphene by random impurities treated in a coherent-potential approximation. Using the analytically solvable Lloyd model for the disorder distribution, we show that the temperature dependence of the minimum conductivity as well as the temperature dependence of the resistivity at high densities and the density dependence of the respective slopes are consistently explained by a temperature dependent disorder strength $\Gamma$ consisting of a constant plus a $T$-linear contribution. This finding suggests that at least two contributions to scattering in graphene are important for its transport properties, and that one of the contributions is due to scattering of electrons from thermally induced excitations.