Localised Magneto-Optical Collective Excitations of Impure Graphene

TL;DR

This paper investigates how impurities in graphene under strong magnetic fields affect localized collective excitations, revealing bound states and their dependence on impurity type and filling factor.

Contribution

It provides a detailed analysis of impurity-induced localized magneto-optical excitations in graphene, considering both long-range and short-range impurities.

Findings

Bound states appear above and below the magnetoplasmon continuum.

Short-range impurities have a less pronounced effect.

Energies and oscillator strengths depend on the filling factor.

Abstract

We study optically-induced collective excitations of graphene in the presence of a strong perpendicular magnetic field and a single impurity. We determine the energies and absorption strengths of these excitations, which become localised on the impurity. Two different types of impurity are considered i. the long-range Coulomb impurity, ii. a delta-function impurity located at either an A or B graphene sublattice site. Both impurity types result in some bound states appearing both above and below the magnetoplasmon continuum, although the effect of the short-range impurity is less pronounced. The dependence of the energies and oscillator strengths of the bound states on the filling factor is investigated.