Boltzmann transport and residual conductivity in bilayer graphene

A Drude-Boltzmann theory is used to calculate the transport properties of bilayer graphene. We find that for typical carrier densities accessible in graphene experiments, the dominant scattering mechanism is overscreened Coulomb impurities that behave like short-range scatterers. We anticipate that the conductivity σ(n) is linear in n at high density and has a plateau at low density corresponding to a residual density of n*=√nᵢₘₚ ̃ \~n, where ̃ \~n is a constant which we estimate, using a self-consistent Thomas-Fermi screening approximation, to be ̃ \~n≈0.01 qTF²≈140×10¹⁰0.3em0excm^-2. Analytic results are derived for the conductivity as a function of the charged impurity density. We also comment on the temperature dependence of the bilayer conductivity.