EFFECTS OF INTERFACE IMPERFECTIONS ON THE ZEEMAN SPLITTING OF EXCITONS IN DILUTED MAGNETIC SEMICONDUCTOR QUANTUM-WELLS

Theoretical estimates are given of the influence that imperfect interf aces have on the Zeeman splittings of excitons in diluted magnetic sem iconductor quantum well structures in which one or both of the barrier s are magnetic. A first-principles theoretical treatment of the micros copic magnetic response of the interfaces has been utilized in the cal culations. The results show how sensitive these splittings can be to e ven the smallest degree of imperfection at the interface region provid ed that both barriers are magnetic and the initial potential profile i s symmetric with respect to the centre of the well. A comparison with experimental data on the CdTe/Cd1-xMnxTe system shows that all such sy mmetric quantum well structures reported to date have imperfections at the interface region extending over at least one or two monolayers. T he calculations also show that asymmetric quantum well structures, in which one of the barriers is non-magnetic, can be a far less sensitive probe of interface imperfections.