A diffusion anomaly in dipole-oriented two-dimensional excitons in GaAs/AlGaAs coupled quantum wells

We have observed an anomaly in the low-temperature photoluminescence of dipole-oriented long-lived excitons in a coupled quantum well under an electrical bias. A discrepancy between the experiment and a Monte Carlo simulation for the exciton diffusion in the system suggests a boson correlation for a two-dimensional Bose system in a random potential with repulsive interaction between bosons. © 1995 Società Italiana di Fisica.