http://www.cnr.it/ontology/cnr/individuo/prodotto/ID32632

Low-energy acoustic plasmons at metal surfaces (Articolo in rivista)

Type

Prodotto della ricerca (Classe)
Articolo in rivista (Classe)

Label

Low-energy acoustic plasmons at metal surfaces (Articolo in rivista) (literal)

Anno

2007-01-01T00:00:00+01:00 (literal)

Http://www.cnr.it/ontology/cnr/pubblicazioni.owl#doi

10.1038/nature05975 (literal)

Alternative label

Diaconescu B. a; Pohl K. a; Vattuone L. b; Savio L. b; Hofmann P. c; Silkin V.M. d; Pitarke J.M. e; Chulkov E.V. d; Echenique P.M. d; Farías D. f; Rocca M. g (2007)
Low-energy acoustic plasmons at metal surfaces
in Nature (Lond.); NATURE PUBLISHING GROUP,, LONDON (Regno Unito)
(literal)

Http://www.cnr.it/ontology/cnr/pubblicazioni.owl#autori

Diaconescu B. a; Pohl K. a; Vattuone L. b; Savio L. b; Hofmann P. c; Silkin V.M. d; Pitarke J.M. e; Chulkov E.V. d; Echenique P.M. d; Farías D. f; Rocca M. g (literal)

Pagina inizio

57 (literal)

Pagina fine

59 (literal)

Http://www.cnr.it/ontology/cnr/pubblicazioni.owl#altreInformazioni

Il lavoro è stato recensito su Le Scienze (literal)

Http://www.cnr.it/ontology/cnr/pubblicazioni.owl#numeroVolume

448 (literal)

Rivista

Nature (Rivista)

Http://www.cnr.it/ontology/cnr/pubblicazioni.owl#numeroFascicolo

7149 (literal)

Note

ISI Web of Science (WOS) (literal)

Http://www.cnr.it/ontology/cnr/pubblicazioni.owl#affiliazioni

a Department of Physics, Material Science Program, University of New Hampshire, Durham, NH 03824, United States; b CNISM, Dipartimento di Fisica, Università di Genova, 16146 Genova, Italy; c Institute for Storage Ring Facilities, Interdisciplinary Nanoscience Center (iNANO), University of Aarhus, 8000 Aarhus C, Denmark; d Donostia International Physics Center (DIPC), Departamento de Fisica de Materiales, Facultad de Ciencias Quimicas, 20018 San Sebastian, Spain; e CIC nanoGUNE Consolider and Materia Kondentsatuaren Fisika Saila, UPV/EHU, Mikeletegi Pasealekua 56, E-2009 Donostia, Basque Country, Spain; f Departamento de Física de la Materia Condensada, Universidad Autónoma de Madrid, 28049 Madrid, Spain; g IMEM-CNR, Dipartimento di Fisica, Università di Genova, 16146 Genova, Italy; (literal)

Titolo

Low-energy acoustic plasmons at metal surfaces (literal)

Abstract

Nearly two-dimensional (2D) metallic systems formed in charge inversion layers and artificial layered materials permit the existence of low-energy collective excitations, called 2D plasmons, which are not found in a three-dimensional (3D) metal. These excitations have caused considerable interest because their low energy allows them to participate in many dynamical processes involving electrons and phonons, and because they might mediate the formation of Cooper pairs in high-transition-temperature superconductors. Metals often support electronic states that are confined to the surface, forming a nearly 2D electron-density layer. However, it was argued that these systems could not support low-energy collective excitations because they would be screened out by the underlying bulk electrons. Rather, metallic surfaces should support only conventional surface plasmons - higher-energy modes that depend only on the electron density. Surface plasmons have important applications in microscopy and sub-wavelength optics, but have no relevance to the low-energy dynamics. Here we show that, in contrast to expectations, a low-energy collective excitation mode can be found on bare metal surfaces. The mode has an acoustic (linear) dispersion, different to the dependence of a 2D plasmon, and was observed on Be(0001) using angle-resolved electron energy loss spectroscopy. First-principles calculations show that it is caused by the coexistence of a partially occupied quasi-2D surface-state band with the underlying 3D bulk electron continuum and also that the non-local character of the dielectric function prevents it from being screened out by the 3D states. The acoustic plasmon reported here has a very general character and should be present on many metal surfaces. Furthermore, its acoustic dispersion allows the confinement of light on small surface areas and in a broad frequency range, which is relevant for nano-optics and photonics applications. (literal)

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