The low temperature exciton transport in Cu2O shows a transition from a diffusive to sonic ballistic regime with increase of excitation power or decrease of temperature, and also well pronounced nonlinearities under two-pulse and under pulse plus cw excitation. These features have been interpreted by the authors of the experiments as a proof of Bose-Einstein condensation (BEC) in the exciton system and its superfluidity. However, we have shown previously that most of these transport phenomena in Cu2O can be quantitatively explained within the nonequilibrium phonon-assisted (phonon wind) model, whereas the superfluid interpretation meets multiple inconsistencies. In the present paper we show that the recent experiments by the same group with spatially separated and/or time delayed two-pulse excitation are as well fully explained by the phonon wind picture.
|Number of pages||6|
|Journal||Physica Status Solidi (A) Applied Research|
|Publication status||Published - Mar 2000|
|Event||Optics of Excitons in Confined Systems (OECS-6) - Ascona, Switz|
Duration: 30 Aug 1999 → 2 Sep 1999