Surface plasmon polaritons in a semi-bounded degenerate plasma: Role of spatial dispersion and collisions

Surface plasmon polaritons (SPPs) in a semi-bounded degenerate plasma (e. g., a metal) are studied using the quasiclassical mean-field kinetic model, taking into account the spatial dispersion of the plasma (due to quantum degeneracy of electrons) and electron-ion (electron-lattice, for metals) collisions. SPP dispersion and damping are obtained in both retarded (omega/k(z) similar to c) and non-retarded (omega/k(z) << c) regions, as well as in between. It is shown that the plasma spatial dispersion significantly affects the properties of SPPs, especially at short wavelengths (less than the collisionless skin depth, lambda less than or similar to c/omega(pe)). Namely, the collisionless (Landau) damping of SPPs (due to spatial dispersion) is comparable to the purely collisional (Ohmic) damping (due to electron-lattice collisions) in a wide range of SPP wavelengths, e. g., from lambda similar to 20 nm to lambda similar to 0.8 nm for SPP in gold at T = 293K and from lambda similar to 400 nm to lambda similar to 0.7 nm for SPPs in gold at T = 100 K. The spatial dispersion is also shown to affect, in a qualitative way, the dispersion of SPPs at short wavelengths lambda less than or similar to c/omega(pe). (C) 2012 American Institute of Physics. [http://dx.doi.org/10.1063/1.4764468]