Charge distribution and screening in layered graphene systems

TL;DR

This paper investigates how external electric fields induce charge distributions in layered graphene and graphite, revealing insulating-like screening in neutral systems and layered screening behavior in doped systems.

Contribution

It provides a detailed theoretical analysis of charge screening and distribution in layered graphene systems using linear response and RPA, highlighting differences between neutral and doped states.

Findings

Neutral systems exhibit insulating-like screening with charge oscillations.

Doped systems show a screening length of 2-3 graphene layers.

Charge oscillations are influenced by inter- and intraband transitions.

Abstract

The charge distribution induced by external fields in finite stacks of graphene planes, or in semiinfinite 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 linear response (RPA). The screening properties are determined by contributions from inter- and intraband electronic transitions. In neutral systems, only interband transitions contribute to the charge polarizability, leading to insulating-like 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 equivalent to 2-3 graphene layers, superimposed to significant charge oscillations.