Nonlocal effects in metallic nanoparticles

For the metallic nanoparticles, smaller than the free electron path, an impact of the particle’s surface on the nonlocal effects emerging is shown. Light-induced current inside the particle begins to depend on the spatial derivatives of the field that leads to modification of Maxwell’s equations. Consequently, the results of Mie theory as well as definitions of the dielectric function and optical conductivity should be revisited. For the sphere-shaped nanoparticle, the explicit expression for the high-frequency current with account of nonlocality is obtained. The dependence of the nonlocal contribution on the light frequency and particle’s size is discussed.