Multipole plasmons and their disappearance in few-nanometre silver nanoparticles

• DOI: 10.1038/ncomms9788
• Publication Date: 2015-11-05T10:24:30Z
• Authors: Søren Raza; Shima Kadkhodazadeh; Thomas Christensen; Marcel Di Vece; Martijn Wubs; N. Asger Mortensen; Nicolas Stenger
• Keywords: Localized surface plasmon

Abstract Electron energy-loss spectroscopy can be used for detailed spatial and spectral characterization of optical excitations in metal nanoparticles. In previous electron experiments on silver nanoparticles with radii smaller than 20 nm, only the dipolar surface plasmon resonance was assumed to play a role. Here, applying individual encapsulated silicon nitride, we observe besides usual dipole an additional corresponding higher angular momenta nanoparticle as small 4 nm. We study radius beam impact position dependence both resonances separately. For particles nm higher-order mode disappears, agreement generalized non-local response theory, while blueshift exceeds our theoretical predictions. Unlike spectra, multipole plasmons are important spectra even ultrasmall metallic