title: Molecular orbital gates for plasmon excitation.
abstract: Future combinations of plasmonics with nanometer-sized electronic circuits require strategies to control the electrical excitation of plasmons at the length scale of individual molecules. A unique tool to study the electrical plasmon excitation with ultimate resolution is scanning tunneling microscopy (STM). Inelastic tunnel processes generate plasmons in the tunnel gap that partially radiate into the far field where they are detectable as photons. Here we employ STM to study individual tris-(phenylpyridine)-iridium complexes on a C60 monolayer, and investigate the influence of their electronic structure on the plasmon excitation between the Ag(111) substrate and an Ag-covered Au tip. We demonstrate that the highest occupied molecular orbital serves as a spatially and energetically confined nanogate for plasmon excitation. This opens the way for using molecular tunnel junctions as electrically controlled plasmon sources.
authors.affiliation: Max-Planck-Institut für Festkörperforschung, Heisenbergstrasse 1, 70569 Stuttgart, Germany.
authors.forename: Theresa
authors.initials: T
authors.lastname: Lutz
authors.forename: Christoph
authors.initials: C
authors.lastname: Grosse
authors.forename: Christian
authors.initials: C
authors.lastname: Dette
authors.forename: Alexander
authors.initials: A
authors.lastname: Kabakchiev
authors.forename: Frank
authors.initials: F
authors.lastname: Schramm
authors.forename: Mario
authors.initials: M
authors.lastname: Ruben
authors.forename: Rico
authors.initials: R
authors.lastname: Gutzler
authors.forename: Klaus
authors.initials: K
authors.lastname: Kuhnke
authors.forename: Uta
authors.initials: U
authors.lastname: Schlickum
authors.forename: Klaus
authors.initials: K
authors.lastname: Kern