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 over-screened Coulomb impurities that behave like short-range scatterers. We anticipate that the conductivity sigma(n) is linear in n at high density and has a plateau at low density corresponding to a residual density of n* = root n(imp)(n) over tilde, where (n) over tilde is a constant which we estimate, using a self- consistent Thomas- Fermi screening approximation, to be (n) over tilde approximate to 0.01 q(TF)(2) approximate to 140 x 10(10) cm(-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.