Theory of carrier transport in bilayer graphene

TL;DR

This paper develops a comprehensive theory for the electrical conductivity of bilayer graphene, considering both long-range and short-range disorder effects, and explains key transport phenomena including density dependence and minimum conductivity.

Contribution

It introduces a detailed model accounting for multiple disorder types and their impact on bilayer graphene's transport properties, highlighting differences from single-layer graphene.

Findings

Conductivity shows linear density dependence at high densities.

Minimum conductivity arises from electron-hole puddles near neutrality.

Both long-range and short-range disorders significantly influence transport.

Abstract

We develop a theory for density, disorder, and temperature dependent electrical conductivity of bilayer graphene in the presence of long-range charged impurity scattering as well as an additional short-range disorder of independent origin, establishing that both scattering mechanisms contribute significantly to determining bilayer transport properties. We find that although strong screening properties of bilayer graphene lead to qualitative differences with the corresponding single layer situation, both systems exhibit the linearly density dependent conductivity at high density and the minimum graphene conductivity behavior around the charge neutrality point due to the formation of inhomogeneous electron-hole puddles induced by the random charged impurity centers.