Surface plasmons at composite surfaces with diffusive charges
B. Horovitz1 and C. Henkel2
Department of Physics, Ben Gurion University - Beer Sheva 84105, Israel
2 Institut für Physik und Astronomie, Universität Potsdam - 14476 Potsdam, Germany, EU
Accepted: 30 January 2012
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.
PACS: 73.20.Mf – Collective excitations (including excitons, polarons, plasmons and other charge-density excitations) / 68.35.Fx – Diffusion; interface formation
© EPLA, 2012