Surface plasmons at composite surfaces with diffusive charges

B. Horovitz¹ and C. Henkel²

¹ Department of Physics, Ben Gurion University - Beer Sheva 84105, Israel
² Institut für Physik und Astronomie, Universität Potsdam - 14476 Potsdam, Germany, EU

Received: 15 September 2011
Accepted: 30 January 2012

Abstract

Metal surfaces with disorder or with nanostructure modifications are studied, allowing for a localized charge layer (CL) in addition to continuous charges (CC) in the bulk, both charges having a compressional or diffusive nonlocal response. The notorious problem of “additional boundary conditions” is resolved with the help of a Boltzmann equation that involves the scattering between the two charge types. Depending on the strength of this scattering, the oscillating charges can be dominantly CC or CL; the surface plasmon (SP) resonance acquires then a relatively small linewidth, in agreement with a large set of data. With a few parameters our model describes a large variety of SP dispersions corresponding to observed data.