title: Quantum plasmonics: optical properties of a nanomatryushka.
abstract: Quantum mechanical effects can significantly reduce the plasmon-induced field enhancements around nanoparticles. Here we present a quantum mechanical investigation of the plasmon resonances in a nanomatryushka, which is a concentric core-shell nanoparticle consisting of a solid metallic core encapsulated in a thin metallic shell. We compute the optical response using the time-dependent density functional theory and compare the results with predictions based on the classical electromagnetic theory. We find strong quantum mechanical effects for core-shell spacings below 5 Å, a regime where both the absorption cross section and the local field enhancements differ significantly from the classical predictions. We also show that the workfunction of the metal is a crucial parameter determining the onset and magnitude of quantum effects. For metals with lower workfunctions such as aluminum, the quantum effects are found to be significantly more pronounced than for a noble metal such as gold.
authors.affiliation: Department of Physics and Astronomy, MS 61, Rice University , Houston, Texas 77005, United States.
authors.forename: Vikram
authors.initials: V
authors.lastname: Kulkarni
authors.forename: Emil
authors.initials: E
authors.lastname: Prodan
authors.forename: Peter
authors.initials: P
authors.lastname: Nordlander
mesh_terms: D006046:Gold / Q000737:chemistry*; D053768:Metal Nanoparticles / Q000737:chemistry*; D055095:Optics and Photonics; D011789:Quantum Theory; D020349:Surface Plasmon Resonance
chemical_list: D006046:Gold