Surface plasmon lifetime in metal nanoshells

TL;DR

This paper presents quantum-mechanical calculations of surface plasmon lifetime in metal nanoshells, revealing that damping decreases with reduced shell thickness and exhibits quantum beats due to interference effects.

Contribution

It introduces a quantum-mechanical approach to analyze Landau damping in nanoshells, showing novel behavior contrary to classical models.

Findings

Damping rate decreases as nanoshell thickness is reduced.

Damping exhibits quantum beats due to interference of electron scattering.

Spatial distribution of plasmon field influences damping behavior.

Abstract

The lifetime of localized surface plasmon plays an important role in many aspects of plasmonics and its applications. In small metal nanostructures, the dominant mechanism restricting plasmon lifetime is size-dependent Landau damping. We performed quantum-mechanical calculations of Landau damping for the bright surface plasmon mode in a metal nanoshell. In contrast to the conventional model based on the electron surface scattering, we found that the damping rate decreases as the nanoshell thickness is reduced. The origin of this behavior is traced to the spatial distribution of plasmon local field inside the metal shell. We also found that, due to interference of electron scattering amplitudes from nanoshell's two metal surfaces, the damping rate exhibits pronounced quantum beats with changing shell thickness.