Landau damping and lifetime oscillation of surface plasmons in metallic thin films studied in a jellium slab model

The lifetime of surface plasmons in metallic thin films has been calculated using linear response theory and time-dependent local density approximation. The linewidth due to Landau damping is found to depend exponentially on the film thickness. It exhibits quantum oscillations in ultrathin films with a period that is about three times longer than the universal period λF/2 observed in other quantities. This period results from the dynamical Friedel oscillations in the collective excitation normal to the films. Its finding has general implications in quantum control of nanoplasmons and their mediated processes across the films and on their surfaces.