Charge distribution and screening in layered graphene systems

The charge distribution induced by external fields in finite stacks of graphene planes, or in semi-infinite graphite is considered. The interlayer electronic hybridization is described by a nearest-neighbor hopping term, and the charge induced by the self-consistent electrostatic potential is calculated within the linear response theory (random phase approximation). The screening properties are determined by contributions from interband and intraband electronic transitions. In neutral systems, only interband transitions contribute to the charge polarizability, leading to insulatinglike screening properties, and to oscillations in the induced charge, with a period equal to the interlayer spacing. In doped systems, we find a screening length that is equivalent to two-to-three graphene layers, superimposed to significant charge oscillations.