Electronic response of graphene to linelike charge perturbations

TL;DR

This paper investigates the nonlinear electrostatic screening of linelike charges in graphene, revealing doping-independent electron density behavior and the formation of p-n junctions, impacting graphene's transport and capacitance properties.

Contribution

It provides a nonlinear analysis of electrostatic screening in graphene, extending beyond linear-response theory and exploring effects on conductance and quantum capacitance.

Findings

Electron density n(x)~(log x)^2/x^2 at intermediate distances

Formation of p-n junctions at larger distances for repulsive perturbations

Implications for transport properties and electrostatic control of graphene

Abstract

The problem of electrostatic screening of a charged line by undoped or weakly doped graphene is treated beyond the linear-response theory. The induced electron density is found to be approximately doping independent, n(x)~(log x)^2/x^2, at intermediate distances x from the charged line. At larger x, twin p-n junctions may form if the external perturbation is repulsive for graphene charge carriers. The effect of such inhomogeneities on conductance and quantum capacitance of graphene is calculated. The results are relevant for transport properties of graphene grain boundaries and for local electrostatic control of graphene with ultrathin gates.