▎ 摘　　要

We systematically calculate thermopower of biased and unbiased multilayer graphene systems. The effect of screening to a bias field perpendicular to the graphene planes is taken into account self-consistently under the Hartree approximation. The model including nearest-neighbor hopping and the more general Slonczewski-Weiss- McClure model are both considered for a comparison. The effect of impurity scattering is studied for monolayer and unbiased bilayer graphene and is treated in terms of the self-consistent Born approximation. For a monolayer graphene, only when the effect of impurity scattering is taken into account, could all the qualitative aspects of the experimental results be correctly reproduced. Besides bilayer graphene, only trilayer graphene opens a small gap and shows a slight enhancement of thermopower under an external bias. The biased bilayer graphene shows the largest thermopower among all the systems studied.