We demonstrate that the long-range transport of excitons in Cu2O, reported in [E. Fortin, et al., Phys. Rev. Lett. 70, 3951 (1993)], as well as its nonlinearity in case the of two-pulse excitation [A. Mysyrowicz, et al., Solid State Commun. 92, 957 (1994)], can be attributed to the nonequilibrium phonon induced drag and cannot be considered as an experimental proof of Bose-Einstein condensation and superfluidity of excitons in Cu2O.
- A. semiconductors
- D. electron-phonon interactions
- D. electronic transport