Résumé:

We suggest a new mechanism of Bose condensation of excitons in a quantum well with semimagnetic barriers. Attraction of excitons is due to their exchange interaction with semimagnetic environment. The long exciton lifetime needed for formation of a condensed phase is provided due to exchange-induced displacement of the hole into one of the barriers leading to formation of a long-living spatially indirect state. The resulted condensed state is a collective exciton magnetic polaron. (C) 1998 Elsevier Science B.V. All rights reserved.