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Saturday, July 26, 2014
Abstract-Plasmon modes in graphene: status and prospect
Plasmons in graphene have unusual properties and offer promising prospect for plasmonic applications covering a wide frequency range, going from terahertz up to the visible. Plasmon modes have been recently studied in both free-standing and supported graphene. Here we review plasmons in graphene, with particular emphasis on plasmonic excitations in epitaxial graphene and on the influence of the underlying substrate on screening pro-cesses. Even if the theoretical comprehension of plasmons in supported graphene is still incomplete, several experimental results provide hints on the nature of plasmonic excita-tions in graphene on metals and semiconductors. Plasmon in graphene can be tuned by chemical doping and gating potentials. We show through selected examples that adsorb-ates may be used to tune the plasmon frequency, while the intercalation of chemical species allows to decouple the graphene sheet from the substrate, so as to recover the plasmon dispersion of pristine graphene. Finally, we will also report on intriguing effects due to many-body interaction, such as the excitations generated by electron-electron coupling (magnetoplasmons) and, moreover, the composite modes arising from the coupling of plasmons with phonons and with charge carriers.