Berlin 2012 – wissenschaftliches Programm
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O: Fachverband Oberflächenphysik
O 34: Poster Session I (Graphene; Plasmonics and nanooptics; Coherence and coherent control in nanophotonics and plasmonics)
O 34.14: Poster
Dienstag, 27. März 2012, 18:15–21:45, Poster E
Microscopic derivation of screened Graphene-Bloch equations — •Eike Verdenhalven1, Ermin Malic1, Rolf Binder2, and Andreas Knorr1 — 1Institut für Theoretische Physik, Technische Universität Berlin, Germany — 2College of Optical Sciences and Department of Physics, University of Arizona, Tucson, USA
The Coulomb interaction is known to be very strong in low-dimensional carbon-nanostructures, such as carbon nanotubes and graphene. Earlier calculations and experiments have revealed that excitonic effects significantly change the optical properties even of metallic nanotubes and graphene [1,2]. However many-particle interaction also leads to the reduction of the Coulomb interaction strength by introducing an internal screening. In this work, we present a fully microscopic derivation of the dielectric function in the static limit. Within a density-matrix formalism we derive screened graphene-Bloch equations and a screened microscopic Boltzmann equation in second order Born-Markov approximation. We calculate the dielectric function in dependence of the momentum transfer along different directions in the Brillouin zone of graphene, showing its highest value of about 4.7 for small momentum transfer.
[1] E. Malić, T. Winzer, E. Bobkin, and A. Knorr, Phys. Rev. B 84, 205406, (2011)
[2] E. Malić, J. Maultzsch, S. Reich, and A. Knorr, Phys. Rev. B 82, 035433 (2010)