On the nature of the plasmon drag effect

Light-matter momentum transfer in plasmonic materials is theoretically discussed in the framework of a plasmonic pressure mechanism taking into account nonequilibrium electron dynamics and the thermalization process. We show that our approach explains the experimentally observed relationship between the plasmon-related electromotive force and the absorption and allows one to correctly predict the magnitude of the plasmon drag electromotive force in flat metal films. We extend our theory to metal films with modulated profiles and show that the simple relationship between plasmonic energy and momentum transfer holds at relatively small amplitudes of height modulation and an approximation of laminar electron drift. The theoretical groundwork is laid for further investigations of shape-controlled plasmon drag in nanostructured metal.