Oscillatory behavior and enhancement of the surface plasmon linewidth in embedded noble metal nanoparticles

TL;DR

This paper investigates how the linewidth of surface plasmons in embedded noble metal nanoparticles oscillates with particle size, influenced by quantum effects and environment, affecting their damping and lifetime.

Contribution

It provides a detailed numerical and semiclassical analysis of size-dependent plasmon linewidth oscillations in nanoparticles embedded in various environments.

Findings

Linewidth oscillates with nanoparticle radius due to spectral density correlations.

Embedding environment significantly affects plasmon lifetime and damping.

Non-monotonous size dependence persists even with unoccupied conduction bands.

Abstract

We study the Landau damping of the surface plasmon resonance of metallic nanoparticles embedded in different environments of experimental relevance. Important oscillations of the plasmon linewidth as a function of the radius of the nanoparticles are obtained from numerical calculations based on the time dependent local density approximation. These size-oscillations are understood, within a semiclassical approximation, as a consequence of correlations in the spectral density of the nanoparticles. We treat inert matrices, as well as the case with an unoccupied conduction band. In the latter case, the plasmon lifetime is greatly reduced with respect to the inert case, but the non-monotonous size-dependence persists.