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Nondiffusive excitonic transport in GaAs and the effects of momentum scattering
Phys. Rev. B 54, R11046(R) – Published 15 October, 1996
DOI: https://doi.org/10.1103/PhysRevB.54.R11046
Abstract
Measurements of exciton transport using frequency-domain nearly degenerate four-wave mixing (NDFWM) show a failure of Fick's law and near-ballistic excitonic motion for scale lengths less than 10 μm. A solution of the Boltzmann transport equation assuming a simple momentum-changing collision model is in agreement with the observed NDFWM line shapes and apparent subquadratic dependence on inverse scale length. The measurements show the surprising result that exciton-exciton interactions lead to a large increase in exciton linewidth with little corresponding change in exciton center-of-mass momentum, unlike exciton interactions with phonons and impurities.