From spatially indirect excitons to momentum-space indirect excitons by an in-plane magnetic field

An in-plane magnetic field is found to change drastically the photoluminescence spectra and kinetics of interwell excitons in GaAs/AlxGa1-xAs coupled quantum wells. This effect is clue to the in-plane magnetic-field-induced displacement of the interwell exciton dispersion in momentum space, which results in the transition from the momentum-space direct exciton ground state to the momentum-space indirect exciton ground state. An in-plane magnetic field is, therefore, an effective tool for exciton dispersion engineering.