Novel low-energy collective excitation at metal surfacesV. M. Silkin1, A. García-Lekue2, J. M. Pitarke1, 2, E. V. Chulkov1, 3, E. Zaremba4 and P. M. Echenique1, 3
1 Donostia International Physics Center (DIPC) and Centro Mixto CSIC-UPV/EHU Manuel de Lardizabal Pasealekua, E-20018 Donostia, Basque Country, Spain
2 Materia Kondentsatuaren Fisika Saila, Zientzi Fakultatea Euskal Herriko Unibertsitatea - 644 Posta kutxatila E-48080 Bilbo, Basque Country, Spain
3 Materialen Fisika Saila, Kimika Fakultatea, Euskal Herriko Unibertsitatea 1072 Posta kutxatila, E-20018 Donostia, Basque Country, Spain
4 Department of Physics, Queen's University - Kingston, Ontario, Canada K7L 3N6
(Received 19 November 2003; accepted in final form 11 February 2004)
A novel collective excitation is predicted to exist at metal surfaces where a two-dimensional surface state band coexists with the underlying three-dimensional continuum. This is a low-energy acoustic plasmon with linear dispersion at small wave vectors. Since new modern spectroscopies are especially sensitive to surface dynamics near the Fermi level, the existence of surface-state-induced acoustic plasmons is expected to play a key role in a large variety of new phenomena and to create situations with potentially new physics.
71.45.Gm - Exchange, correlation, dielectric and magnetic response functions, plasmons.
73.20.At - Surface states, band structure, electron density of states.
73.50.Gr - Charge carriers: generation, recombination, lifetime, trapping, mean free paths.
© EDP Sciences 2004