Exchange interactions in CdMnTe/CdMgTe quantum wells under high magnetic fields

The sp–d exchange interaction Jsp–d and the exchange interaction between the nearest neighbor Mn ions JNN were studied by magneto-photoluminescence spectra of excitons in CdMnTe/CdMgTe quantum wells in pulsed high magnetic fields up to View the MathML source. The magnitude of Jsp–d estimated from the observed Zeeman splitting was found to decrease as the quantum well width was decreased. The decrease is partly due to the penetration of the electron and the hole wave functions into the non-magnetic CdMgTe barrier layers, and partly due to the k-dependence of the exchange interaction. It was found that the latter effect is much larger than theoretically predicted. The observed features are well explained by a model assuming the interface disorder within some thickness near the interface. In contrast to Jsp–d, the nearest neighbor interaction JNN estimated from the steps in the photoluminescence peak was found to be independent of the well width.