Spectral and optical properties of doped graphene with charged impurities in the self-consistent Born approximation

Spectral and transport properties of doped (or gated) graphene with long-range charged impurities are discussed within the self-consistent Born approximation. It is shown how, for impurity concentrations n(imp) greater than or similar to n a finite density of states appears at the Dirac point, the one-particle lifetime no longer scales linearly with the Fermi momentum, and the line shapes in the spectral function become non-Lorentzian. These behaviors are different from the results calculated within the Born approximation. We also calculate the optical conductivity from the Kubo formula by using the self-consistently calculated spectral function in the presence of charged impurities.