Surface plasmon excitation and correlation-induced localization-delocalization transition in semicontinuous metal films

By solving the surface plasmon (SP) eigenproblem, a scaling theory is developed for the electromagnetic response of semicontinuous metal films. It is shown that short-range correlations in the governing Kirchhoff Hamiltonian result in delocalization of the SP eigenmodes in the center of the spectrum. The subset of those modes has a zero measure so that their relative weight in the spectrum becomes asymptotically small for large systems. Still, the singularity caused by the delocalized states results in modification of the critical indices for the high-order field moments and thus affects the optical properties of the composite. Comparison between the developed theory and exact numerical calculations reveals excellent agreement.