Condensation of Indirect Excitons in Coupled AlAs/GaAs Quantum Wells

The photoluminescence of excitons confined in an electric field tunable coupled AlAs/GaAs quantum well has been investigated at $T\ensuremath{\ge}350$ mK and magnetic fields $H\ensuremath{\le}14$ T. In the indirect regime where electrons and holes are separated both in real and in $k$ space, the magnetic field was found to result in (i) a strong change of both the photoluminescence intensity and decay time which is attributed to anomalies in the exciton transport and (ii) an appearance of a huge broad band noise in the photoluminescence intensity which is evidence for exciton condensation.