Nonlocal effects in metallic nanoparticles: the kinetic approach outlook

TL;DR

This paper explores how nonlocal effects influence the optical properties of metallic nanoparticles smaller than the electron mean free path, modifying classical theories and providing explicit formulas for spherical particles.

Contribution

It introduces a kinetic approach to account for nonlocal effects in metallic nanoparticles, revising Maxwell's equations and deriving explicit expressions for spherical particles.

Findings

Nonlocal effects depend on particle size and light frequency.

Classical Mie theory and dielectric functions require revision for small nanoparticles.

Explicit high-frequency current expressions are derived for sphere-shaped nanoparticles.

Abstract

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.