Influence of correlated impurities on conductivity of graphene sheets: Time-dependent real-space Kubo approach

TL;DR

This study uses a time-dependent real-space Kubo approach to numerically analyze how correlated impurities affect graphene's conductivity, finding no enhancement due to correlations in disorder distribution.

Contribution

It provides the first detailed numerical analysis showing that impurity correlations do not increase graphene conductivity, challenging previous assumptions about dopant correlation effects.

Findings

Correlations in impurity distribution do not enhance conductivity.

Temperature effects on conductivity are likely due to factors other than impurity correlations.

Numerical results contradict earlier experimental interpretations.

Abstract

Exact numerical calculations of the conductivity of graphene sheets with random and correlated distributions of disorders have been performed using the time-dependent real-space Kubo formalism. The disorder was modeled by the long-range Gaussian potential describing screened charged impurities and by the short-range potential describing neutral adatoms both in the weak and strong scattering regime. Our central result is that correlation in the spatial distribution for the strong short-range scatterers and for the long-range Gaussian potential do not lead to any enhancement of the conductivity in comparison to the uncorrelated case. Our results strongly indicate that the temperature enhancement of the conductivity reported in the recent study (Yan and Fuhrer, Phys. Rev. Lett. 107, 206601 (2011)) and attributed to the effect of dopant correlations was most likely caused by other factors not related to the correlations in the scattering potential.