language: en

[Confidential: not for distribution. Submitted to IOP Publishing for peer review]

10 December 2009

Sputtering-induced modification of the electronic properties of Ag/Cu(111)

A. Politano 1,2,3 and G. Chiarello 1,4
1 Università degli Studi della Calabria, Dipartimento di Fisica
87036 Rende (Cs), Italy
2 Departamento de Fisica de la Materia Condensada, Universidad Autónoma de Madrid
28049 Madrid, Spain.
3 Instituto Madrileño de Estudios Avanzados (IMDEA) en Nanociencia
28049 Madrid, Spain
4 CNISM, Consorzio Nazionale Interuniversitario per le Scienze Fisiche della Materia,
via della Vasca Navale 84, 00146 Roma, Italy

Abstract High-resolution electron energy loss spectroscopy has been used to study the electronic properties of Ag thin films deposited on Cu(111) and modified by Ar + sputtering. Ion sputtering strongly modifies the loss function in the region of single-particle transition as deduced from the appearance of sputtering-induced spectral features in the valence band. In contrast with unmodified Ag systems, in sputtered films the centroid of the induced charge of the surface plasmon lies in the close nearness of the jellium edge. In these modified Ag films, Landau damping processes are activated beyond a critical energy of 3.83 eV and a threshold wave-vector of 0.2 Å -1 . Moreover, we found that plural plasmonic losses arose upon increasing Ar + dose. A comparison with the case of the sputtered Ag(100) surface is presented throughout the paper.

1 Introduction