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Inequivalent effect of Dirac valleys on low‐energy plasmons in heavily doped graphene (Phys. Status Solidi B 6/2016)
Author(s) -
Ta Ho S.,
Anh Le H.,
Le T.,
Nam Do V.
Publication year - 2016
Publication title -
physica status solidi (b)
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.51
H-Index - 109
eISSN - 1521-3951
pISSN - 0370-1972
DOI - 10.1002/pssb.201670538
Subject(s) - plasmon , graphene , brillouin zone , condensed matter physics , anisotropy , physics , dirac fermion , electron , lattice (music) , doping , optics , quantum mechanics , acoustics
The back‐cover page is designed to highlight a new understanding of the low‐energy plasmonic behaviours of graphene, including the possibility of observing a special plasmon mode beside the conventional mode of two‐dimensional fermions in the case of heavily doped graphene, and the anisotropy of the plasmon modes – cf. the article by Van Nam Do and coworkers on pp. 1186–1194 . The background image shows a hexagonal lattice for graphene, shaded in form of a set of color rings – not in the shape of circles, but of rounded triangles. These color rings illustrate the anisotropic propagation of the electron density oscillation in the graphene lattice as waves, i.e. plasmons. The anisotropy and the formation of plasmon modes stem from the anisotropy and the inequivalence of the energy surfaces in the two Dirac valleys centered at the K‐ and K'‐points in the Brillouin zone. These points are highlighted by the picture of the distribution of the group velocity of electron states together with the energy contours (see right image). The two left images, showing the electron energy loss spectrum and the plasmonic dispersion curves, respectively, point to the main finding of the novel plasmon mode.