title: Multipole surface plasmon resonances in conductively coupled metal nanowire dimers.
abstract: We report on the experimental and the theoretical investigation of multipole surface plasmon resonances in metal nanowires conductively connected by small junctions. The influence of a conductive junction on the resonance energies of nanowire dimers was simulated using the finite element method based software CST Microwave Studio and experimentally measured by electron energy-loss spectroscopy in a transmission electron microscope. We extend the analysis of conductively connected structures to higher order multipole modes up to third order, including dark modes. Our results reveal that an increase in junction size does not shift significantly the antibonding modes, but causes a strong blue shift of the bonding modes, leading to an energetic rearrangement of the modes compared to those of a capacitively coupled dimer with similar dimensions.
authors.affiliation: Materials Research Department, GSI Helmholtzzentrum für Schwerionenforschung GmbH, Darmstadt, Germany. i.alber@gsi.de
authors.forename: Ina
authors.initials: I
authors.lastname: Alber
authors.forename: Wilfried
authors.initials: W
authors.lastname: Sigle
authors.forename: Frank
authors.initials: F
authors.lastname: Demming-Janssen
authors.forename: Reinhard
authors.initials: R
authors.lastname: Neumann
authors.forename: Christina
authors.initials: C
authors.lastname: Trautmann
authors.forename: Peter A
authors.initials: PA
authors.lastname: van Aken
authors.forename: Maria Eugenia
authors.initials: ME
authors.lastname: Toimil-Molares
mesh_terms: D003198:Computer Simulation; D019281:Dimerization; D004553:Electric Conductivity; D008027:Light; D053768:Metal Nanoparticles / Q000737:chemistry* / Q000648:ultrastructure; D008956:Models, Chemical; D012542:Scattering, Radiation; D020349:Surface Plasmon Resonance / Q000379:methods*