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Edge plasmons in graphene
Last modified: 2012-01-02
Abstract
Plasmon modes in graphene are influenced by the unusual dispersion relation of the material. For bulk plasmons this results in
a $n^{1/4}$ dependence of the plasma frequency on the charge density, as opposed to the $n^{1/2}$ dependence in two-dimensional
electron gas; yet, bulk plasmon dispersion in graphene follows a similar $q^{1/2}$ behavior as for other two-dimensional
materials. In this work we consider finite graphene nanostructures, semi-infinite sheets and circular disks, and study edge
plasmons that are confined to the boundaries of the structures. We find that for abrupt edges graphene edge plasmons behave
analogously to those in 2DEGs, but for gradual edge profiles, important distinctions arise. In particular, we show that for a
linear edge profile, graphene supports fewer edge modes than a 2DEG, and the edge monopole plasmon dispersion in graphene
follows a $q^{1/4}$ law in contrast to the $q^0$ behavior seen in 2DEGs.
a $n^{1/4}$ dependence of the plasma frequency on the charge density, as opposed to the $n^{1/2}$ dependence in two-dimensional
electron gas; yet, bulk plasmon dispersion in graphene follows a similar $q^{1/2}$ behavior as for other two-dimensional
materials. In this work we consider finite graphene nanostructures, semi-infinite sheets and circular disks, and study edge
plasmons that are confined to the boundaries of the structures. We find that for abrupt edges graphene edge plasmons behave
analogously to those in 2DEGs, but for gradual edge profiles, important distinctions arise. In particular, we show that for a
linear edge profile, graphene supports fewer edge modes than a 2DEG, and the edge monopole plasmon dispersion in graphene
follows a $q^{1/4}$ law in contrast to the $q^0$ behavior seen in 2DEGs.
Keywords
Graphene plasmonics