Specific features of electric charge screening in few-layer graphene films

We present a nonlinear Thomas-Fermi theory which describes the electric charge screening in a system including two charged substrate layers separated by a few-layered graphene film. We show that by increasing the charge at the interfaces, the system can be turned from the weak screening regime where the whole film responds to the external charge to the strong screening regime where the external charge is screened by a surface charge distribution confined to the bounding graphene layers. The transition from weak to strong screening is shown to turn on relatively quickly, and it occurs when the applied external charge/external field reaches a certain crossover magnitude. The possibilities for experimental observation of the predicted crossover are discussed.