Localized Collective Excitations in Doped Graphene in Strong Magnetic Fields
Abstract
We consider collective excitations in graphene with filled Landau levels (LL's) in the presence of an external potential due to a single charged donor D+ or acceptor A- impurity. We show that localized collective modes split off the magnetoplasmon continuum and, in addition, quasibound states are formed within the continuum. A study of the evolution of the strengths and energies of magneto-optical transitions is performed for integer filling factors nu = 1, 2, 3, 4 of the lowest LL. We predict impurity absorption peaks above as well as below the cyclotron resonance. We show that the single particle electron-hole symmetry of graphene leads to a duality between the spectra of collective modes for the D+ and A-. The duality shows up as a set of the D+ and A- magneto-absorption peaks having same energies, but active in different circular polarizations.
Keywords
Cite
@article{arxiv.0902.4176,
title = {Localized Collective Excitations in Doped Graphene in Strong Magnetic Fields},
author = {A. M. Fischer and A. B. Dzyubenko and R. A. Roemer},
journal= {arXiv preprint arXiv:0902.4176},
year = {2009}
}
Comments
5 pages, 5 figures (only 3 captions). Included a more qualitative discussion of the results and method, in particular addressing the issue of screening. Paper lengthened and more references added