6533b858fe1ef96bd12b5b7a
RESEARCH PRODUCT
Evidence of delocalized excitons in amorphous solids
Marco CannasEleonora VellaFabrizio MessinaRoberto Boscainosubject
Condensed Matter - Materials ScienceMaterials scienceCondensed matter physicsPhononExcitonMaterials Science (cond-mat.mtrl-sci)FOS: Physical sciencesvacuum ultraviolet absorptionGeneral Physics and AstronomyExcitons; amorphous materials; vacuum ultraviolet absorptionResonance (chemistry)Condensed Matter::Disordered Systems and Neural NetworksSpectral lineAmorphous solidDelocalized electronCondensed Matter::Materials ScienceAttenuation coefficientddc:550Excitonamorphous materialEnergy (signal processing)description
We studied the temperature dependence of the absorption coefficient of amorphous ${\mathrm{SiO}}_{2}$ in the range from 8 to 17.5 eV obtained by Kramers-Kronig dispersion analysis of reflectivity spectra. We demonstrate the main excitonic resonance at 10.4 eV to feature a close Lorentzian shape redshifting with increasing temperature. This provides a strong evidence of excitons being delocalized notwithstanding the structural disorder intrinsic to amorphous ${\mathrm{SiO}}_{2}$. Excitons turn out to be coupled to an average phonon mode of 83 meV energy.
| year | journal | country | edition | language |
|---|---|---|---|---|
| 2010-06-29 |