Plasmon-related electric effects in various plasmonic materials*

Significant photoinduced DC electrical effects (currents and potentials) observed in metal films and nanostructures are promising for various applications and present interest from the fundamental physics perspective. They are clearly associated with plasmon excitations, and are the result of strong fields and high field gradients of strongly confined plasmonic fields. In our work, we consider these factors and theoretically estimate effective plasmonic pressure (associated with momentum transfer) and pondermotive forces acting on free carriers, in several plasmonic materials such as silver, gold, copper, aluminum, permalloy, and titanium nitride. Analytical calculations are done using accepted values of optical, electrical, and thermal parameters for each of the materials involved. We consider surface plasmon polariton excitation in a flat geometry and analyze the role of these factors in the generation of photoinduced currents and surface charges. The effects of nonhomogeneous heating are considered as well. Theoretical predictions are compared with experimental results.