Details

Autor(en) / Beteiligte

• Raza, Søren
• Kadkhodazadeh, Shima
• Christensen, Thomas
• Di Vece, Marcel
• Wubs, Martijn
• Mortensen, N. Asger
• Stenger, Nicolas

Titel

Multipole plasmons and their disappearance in few-nanometre silver nanoparticles

Ist Teil von

• Nature communications, 2015-11, Vol.6 (1), p.8788-8788, Article 8788

Ort / Verlag

London: Nature Publishing Group UK

Erscheinungsjahr

2015

Quelle

Elektronische Zeitschriftenbibliothek - Frei zugängliche E-Journals

Beschreibungen/Notizen

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