Subdiffusive exciton motion in systems with heavy-tailed disorder.
J Chem Phys
; 138(21): 214316, 2013 Jun 07.
Article
en En
| MEDLINE
| ID: mdl-23758380
ABSTRACT
We study the transport of collective excitations (Frenkel excitons) in systems with static disorder in the transition energies, not limiting ourselves to Gaussian transition energy distributions. Instead, we generalize this model to the wider class of Lévy stable distributions, characterized by heavy tails. Phonon-assisted scattering of excitons, localized by the disorder, leads to thermally activated exciton motion. The time evolution of the second moment of the exciton distribution is shown to be sublinear, thus indicating that the exciton dynamics in such systems is not diffusive, but rather subdiffusive instead. The heavier the tail in the transition energy distribution is, the larger are the deviations from the diffusive regime. This from fluctuations of site energies larger than the exciton band width (outliers). We show that the occurrence of subdiffusive transport for heavy-tailed disorder distributions can be understood from the scattering rate distributions, which possess a (second) peak at zero scattering rate.
Texto completo:
1
Bases de datos:
MEDLINE
Idioma:
En
Revista:
J Chem Phys
Año:
2013
Tipo del documento:
Article
País de afiliación:
Países Bajos