Size-Dependent Surface Plasmon Dynamics in Metal Nanoparticles

TL;DR

This paper investigates how Coulomb correlations influence ultrafast optical responses in small metal nanoparticles, revealing size-dependent surface plasmon effects that align with experimental observations.

Contribution

It introduces a self-consistent model showing size-dependent many-body effects on surface plasmon dynamics in metal nanoparticles.

Findings

Size-dependent relaxation times near surface plasmon resonance

Surface-induced dynamical screening affects electron interactions

Agreement with recent femtosecond pump-probe experiments

Abstract

We study the effect of Coulomb correlations on the ultrafast optical dynamics of small metal particles. We demonstrate that a surface-induced dynamical screening of the electron-electron interactions leads to quasiparticle scattering with collective surface excitations. In noble-metal nanoparticles, it results in an interband resonant scattering of d-holes with surface plasmons. We show that this size-dependent many-body effect manifests itself in the differential absorption dynamics for frequencies close to the surface plasmon resonance. In particular, our self-consistent calculations reveal a strong frequency dependence of the relaxation, in agreement with recent femtosecond pump-probe experiments.