Lifetime of the surface magnetoplasmons in metallic nanoparticles

TL;DR

This paper investigates how external magnetic fields influence surface magnetoplasmons in metallic nanoparticles, revealing that while the main surface plasmon's lifetime remains unchanged, the magnetoplasmons exhibit weak field-dependent lifetime variations.

Contribution

It provides a theoretical analysis of magnetic field effects on surface magnetoplasmons' frequencies and lifetimes in metallic nanoparticles, including experimental suggestions.

Findings

Surface plasmon lifetime is unaffected by magnetic fields.

Surface magnetoplasmons show weak magnetic-field dependence.

Distinct behaviors of plasmon components under magnetic influence.

Abstract

We study the influence of an external magnetic field on the collective electronic excitations in metallic nanoparticles. While the usual surface plasmon corresponding to the collective oscillation of the electrons with respect to the ionic background persists in the direction parallel to the magnetic field, the components in the perpendicular plane are affected by the field and give rise to two collective modes with field-dependent frequencies, the surface magnetoplasmons. We analyze the decay of these collective excitations by their coupling to particle-hole excitations and determine how their lifetimes are modified by the magnetic field. In particular, we show that the lifetime of the usual surface plasmon is not modified by the magnetic field, while the lifetime of the two surface magnetoplasmons present a weak magnetic-field dependence. Optical spectroscopy experiments are suggested in which signatures of the surface magnetoplasmons may be observed.