Graphene plasmons: impurities and nonlocal effects

TL;DR

This paper investigates how surface impurities and nonlocal effects influence graphene's optical conductivity and plasmon behavior, revealing impurity-induced modifications and potential sensing applications.

Contribution

It introduces a comprehensive analysis of impurity effects on graphene plasmons using self-consistent Green's functions, including nonlocal effects and experimental implications.

Findings

Impurities create an impurity band affecting plasmon dispersion.

Impurity density and strength determine the impurity band's properties.

Impurity effects significantly alter electromagnetic response and plasmon losses.

Abstract

This work analyses how impurities and vacancies on the surface of a graphene sample affect its optical conductivity and plasmon excitations. The disorder is analysed in the self-consistent Green's function formulation and nonlocal effects are fully taken into account. It is shown that impurities modify the linear spectrum and give rise to an impurity band whose position and width depend on the two parameters of our model, the density and the strength of impurities. The presence of the impurity band strongly influences the electromagnetic response and the plasmon losses. Furthermore, we discuss how the impurity-band position can be obtained experimentally from the plasmon dispersion relation and discuss this in the context of sensing.