The Influence of the Percolation Transition on the Electric Conductive and Optical Properties of Ultrathin Metallic Films

The results of the study of the peculiarities of changes in the electrophysical, optical, and plasmonic properties of ultrathin metallic films during the percolation transition from an islet structure to a continuous one have been presented. It has been shown that the change in electrical conductivity of thin Ti and Pt films above the percolation threshold during their condensation can be well described in the framework of the classical percolation theory. The influence of percolation transition in Au metal films on the change of plasmon resonance type from a surface (propagating plasmon-polaritons) to a localized one has been investigated. It has been shown that there is a decrease in the Q-factor of the resonance of surface plasmonic-polaritons during the transition of the film to the granular state near the percolation transition caused by the emergence of conditions for the excitation of localized plasmons. The percolation threshold has been determined for all studied coatings.