Size-dependent correlation effects in the ultrafast optical dynamics of metal nanoparticles
| Autor: | Ilias E. Perakis, T. V. Shahbazyan |
|---|---|
| Rok vydání: | 1999 |
| Předmět: |
Materials science
Scattering Condensed Matter (cond-mat) Relaxation (NMR) Surface plasmon FOS: Physical sciences Physics::Optics Condensed Matter 02 engineering and technology 021001 nanoscience & nanotechnology 01 natural sciences Resonance (particle physics) Molecular physics 3. Good health Scattering rate 0103 physical sciences Quasiparticle Atomic physics 010306 general physics 0210 nano-technology Plasmon Localized surface plasmon |
| Zdroj: | Physical Review B. 60:9090-9099 |
| ISSN: | 1095-3795 0163-1829 |
| Popis: | We study the role of collective surface excitations in the electron relaxation in small metal particles. We show that the dynamically screened electron-electron interaction in a nanoparticle contains a size-dependent correction induced by the surface. This leads to new channels of quasiparticle scattering accompanied by the emission of surface collective excitations. We calculate the energy and temperature dependence of the corresponding rates, which depend strongly on the nanoparticle size. We show that the surface-plasmon-mediated scattering rate of a conduction electron increases with energy, in contrast to that mediated by a bulk plasmon. In noble-metal particles, we find that the dipole collective excitations (surface plasmons) mediate a resonant scattering of d-holes to the conduction band. We study the role of the latter effect in the ultrafast optical dynamics of small nanoparticles and show that, with decreasing nanoparticle size, it leads to a drastic change in the differential absorption lineshape and a strong frequency dependence of the relaxation near the surface plasmon resonance. The experimental implications of our results in ultrafast pump-probe spectroscopy are also discussed. Comment: 29 pages including 6 figures |
| Databáze: | OpenAIRE |
| Externí odkaz: |
|