title: Dirac-like plasmons in honeycomb lattices of metallic nanoparticles.
abstract: We consider a two-dimensional honeycomb lattice of metallic nanoparticles, each supporting a localized surface plasmon, and study the quantum properties of the collective plasmons resulting from the near-field dipolar interaction between the nanoparticles. We analytically investigate the dispersion, the effective Hamiltonian, and the eigenstates of the collective plasmons for an arbitrary orientation of the individual dipole moments. When the polarization points close to the normal to the plane, the spectrum presents Dirac cones, similar to those present in the electronic band structure of graphene. We derive the effective Dirac Hamiltonian for the collective plasmons and show that the corresponding spinor eigenstates represent Dirac-like massless bosonic excitations that present similar effects to electrons in graphene, such as a nontrivial Berry phase and the absence of backscattering off smooth inhomogeneities. We further discuss how one can manipulate the Dirac points in the Brillouin zone and open a gap in the collective plasmon dispersion by modifying the polarization of the localized surface plasmons, paving the way for a fully tunable plasmonic analogue of graphene.
authors.affiliation: Institut de Physique et Chimie des Matériaux de Strasbourg, Université de Strasbourg, CNRS UMR 7504, 23 rue du Loess, BP 43, F-67034 Strasbourg Cedex 2, France.
authors.forename: Guillaume
authors.initials: G
authors.lastname: Weick
authors.forename: Claire
authors.initials: C
authors.lastname: Woollacott
authors.forename: William L
authors.initials: WL
authors.lastname: Barnes
authors.forename: Ortwin
authors.initials: O
authors.lastname: Hess
authors.forename: Eros
authors.initials: E
authors.lastname: Mariani
mesh_terms: D004601:Elementary Particles; D006108:Graphite / Q000737:chemistry; D053768:Metal Nanoparticles / Q000737:chemistry*; D008962:Models, Theoretical; D011789:Quantum Theory; D020349:Surface Plasmon Resonance
chemical_list: D006108:Graphite