LOCALIZABILITY AND DEPHASING OF DIPOLAR EXCITONS IN TOPOLOGICALLY DISORDERED-SYSTEMS

Journal article

We develop a self-consistent theory for the localizability of dipolar excitations, and the interplay between localization and dephasing mechanisms such as exciton-phonon coupling, within the framework of a tight-binding model of topologically disordered systems. When the dephasing rate vanishes the pure Anderson localization problem may be examined, and we find that dipolar excitations are always extended at any finite density. For sufficiently small number density, however, it is found that while no state in the band is ever strictly localized, the excitation transfer rate is exponentially small, and on the time scale of many experimental probes the excitation would effectively appear to be localized. In the limit of rapid dephasing the present theory correlates with the usual master equation treatments of incoherent (Förster) transport. For sufficiently large disorder, examination of the excitation transfer rate as a function of the dephasing rate predicts a nonmonotonic but continuous crossover from coherent to incoherent transport. © 1987 American Institute of Physics.

Authors: Logan, D; Wolynes, P

• Publication status: Published
• Journal: JOURNAL OF CHEMICAL PHYSICS
• Volume: 87
• Issue: 12
• Pages: 7199-7207
• Publication date: 1987-12-15
• DOI: 10.1063/1.453363
• ISSN: 0021-9606