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

TL;DR

This paper investigates how charged impurities affect the spectral and optical properties of doped graphene, revealing non-linear behaviors and non-Lorentzian spectral features at high impurity concentrations.

Contribution

It introduces a self-consistent approach to analyze impurity effects on graphene's spectral and optical properties, highlighting differences from traditional Born approximation results.

Findings

Finite density of states at the Dirac point for high impurity concentrations

Non-linear scaling of one-particle lifetime with Fermi momentum

Non-Lorentzian spectral lineshapes in the spectral function

Abstract

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 $n_{imp}\gtrsim n$ a finite DOS appears at the Dirac point, the one-particle lifetime no longer scales linearly with the Fermi momentum, and the lineshapes 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.