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 the short-range impurity potential. It is proven that the conductivity following from the classical Boltzmann equation picture, where electrons or holes have scattering amplitude reduced due to chirality, is justified except for an exponentially narrow range of chemical potential near the conical point. When in this range, creation of an infinite number of electron-hole pairs related to the quasirelativistic 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.

• Received 19 July 2007

DOI:https://doi.org/10.1103/PhysRevB.76.235425