Generalized kinetic equations for charge carriers in graphene

TL;DR

This paper derives generalized kinetic equations for charge carriers in graphene, showing that classical Boltzmann conductivity is valid except near the Dirac point where quantum effects cause notable corrections.

Contribution

It introduces a new set of kinetic equations for Dirac fermions in graphene and analyzes the limits of classical conductivity models near the conical point.

Findings

Classical Boltzmann conductivity is justified away from the Dirac point.

Near the Dirac point, electron-hole pair creation leads to conductivity renormalization.

Logarithmic corrections to conductivity resemble Kondo effect phenomena.

Abstract

A system of generalized kinetic equations for the distribution functions of two-dimensional Dirac fermions scattered by impurities is derived in the Born approximation with respect to short-range impurity potential. It is proven that the conductivity following from classical Boltzmann equation picture, where electrons or holes have scattering amplitude reduced due chirality, is justified except for an exponentially narrow range of chemical potential near the conical point. When in this range, creation of infinite number of electron-hole pairs related to quasi-relativistic nature of electrons in graphene results in a renormalization of minimal conductivity as compared to the Boltzmann term and logarithmic corrections in the conductivity similar to the Kondo effect.