ENERGY RELAXATION AND TRANSPORT OF INDIRECT EXCITONS IN ALAS GAAS COUPLED QUANTUM-WELLS IN MAGNETIC-FIELD/

The evolution of indirect exciton luminescence in AlAs/GaAs coupled qu antum wells after excitation by pulsed laser radiation has been studie d in strong magnetic fields (B less than or equal to 12 T) at low temp eratures (T greater than or equal to 1.3 K), both in the normal regime and under conditions of anomalously fast exciton transport, which is an indication of the onset of exciton superfluidity. The energy relaxa tion rate of indirect excitons measured in the range of relaxation tim es between several and several hundreds of nanoseconds is found to be controlled by the properties of the exciton transport, specifically, t his parameter increases with the coefficient of excitonic diffusion. T his behavior is qualitatively explained in terms of migration of excit ons between local minima of the random potential in the plane of the q uantum well. (C) 1998 American Institute of Physics. [S1063-7761(98)02 509-8].