Screening induced temperature dependent transport in 2D graphene

TL;DR

This paper models the temperature-dependent electrical conductivity of 2D graphene considering Coulomb impurity screening, revealing a non-monotonic behavior driven by electronic mechanisms without phonons.

Contribution

It introduces a theoretical framework for graphene conductivity that accounts for temperature-dependent Coulomb screening and energy averaging, without involving phonons.

Findings

Conductivity decreases at low temperatures and increases at high temperatures.

The theory highlights the role of dielectric function and energy averaging in temperature dependence.

Comparison with semiconductor 2D systems clarifies unique graphene behavior.

Abstract

We calculate the temperature dependent conductivity of graphene in the presence of randomly distributed Coulomb impurity charges arising from the temperature dependent screening of the Coulomb disorder without any phonons. The purely electronic temperature dependence of our theory arises from two independent mechanisms: the explicit temperature dependence of the finite temperature dielectric function $\epsilon(q,T)$ and the finite temperature energy averaging of the transport scattering time. We find that the calculated temperature dependent conductivity is non-monotonic, decreasing with temperature at low temperatures, and increasing at high temperatures. We provide a critical comparison with the corresponding physics in semiconductor-based parabolic band 2D electron gas systems.