Screening-Induced Transport at Finite Temperature in Bilayer Graphene

TL;DR

This paper investigates how temperature affects charge transport in bilayer graphene, revealing a transition from metallic to insulating behavior due to Coulomb impurity scattering and polarizability changes.

Contribution

It provides a detailed calculation of temperature-dependent conductivity in bilayer graphene considering Coulomb impurity effects within the random phase approximation.

Findings

Polarizability equals the density of states at zero momentum transfer.

Conductivity transitions from linear to quadratic temperature dependence with increasing temperature.

Sharp cusp at $q=2k_F$ becomes smooth at higher temperatures.

Abstract

We calculate the temperature-dependent charge carrier transport of bilayer graphene (BLG) impacted by Coulomb impurity scattering within the random phase approximation. We find the polarizability is equal to the density of states at zero momentum transfer and is enhanced by a factor $\log{4}$ at large momentum transfer for arbitrary temperature. The sharp cusp of static polarizability at $q=2k_F$, due to the strong backward scattering, would be smooth by the increasing temperatures. We also obtain the asymptotic behaviors of conductivity of BLG at low and high temperature, and find it turns from a two dimensional electron gas (2DEG) like linear temperature metallic behavior to a single layer graphene (SLG) like quadratic temperature insulating behavior as the temperature increases.