Dielectric function and plasmons in graphene

, and

Published 4 August 2009 Europhysics Letters Association
, , Citation A. Hill et al 2009 EPL 87 27005 DOI 10.1209/0295-5075/87/27005

0295-5075/87/2/27005

Abstract

The electromagnetic response of graphene and the spectrum of collective plasmon excitations are studied as a function of wave vector and frequency. Our calculation is based on the tight-binding band structure, including both valleys. As a result, near the Dirac points we find plasmons whose dispersion is similar to that obtained in the single-valley approximation by Dirac fermions with some anisotropy though. In contrast to the calculation for a single Dirac cone, we find a stronger damping of the plasmon modes due to interband absorption. Our calculation also reveals effects due to deviations from the linear Dirac spectrum as we increase the Fermi energy, indicating an anisotropic behavior with respect to the wave vector of the external electromagnetic field.

Export citation and abstract BibTeX RIS