Magneto-optics of the spatially separated electron and hole layers in GaAs/AlxGa1-xAs coupled quantum wells

We report on the magneto-optical study of the spatially separated electron and hole layers in GaAs/AlxGa1-xAs coupled quantum wells at low temperatures T greater than or equal to 50 mK and high magnetic fields B less than or equal to 16 T. At high magnetic fields cusps are observed in the energy and intensity of the indirect (interwell) exciton photoluminescence. We tentatively attribute these to the commensurability effects of the magnetoexciton with island structures in the sample. The indirect exciton lifetime is found to increase with magnetic field. The increase is attributed to the reduction of indirect exciton localization area caused by the increase of the magnetoexciton mass. The indirect exciton photoluminescence energy is found to enhance with density, which reflects the net repulsive interaction between indirect excitons.