MAGNETOOPTICAL STUDY OF HEAVY-HOLE AND LIGHT-HOLE EXCITONS IN CDTE (CD, MN)TE SINGLE QUANTUM-WELLS/

We report experimental and theoretical investigations of excitons in C dTe/Cd1-xMnxTe single quantum wells with high manganese content x = 0. 20 and various well widths. The Zeeman splitting of the excitonic tran sitions is measured by photoluminescence excitation in an external mag netic field up to 7.5 T. We have developed an extended model describin g the Zeeman splitting of quantum well excitons, including the exchang e interaction, the intrinsic g-factor of electron and hole and the Cou lomb interaction in an external magnetic field. The calculation allows the interpretation of both light- and heavy-hole excitons. From the Z eeman splittings we deduce the natural valence band offset Q(V) in the strain-free limit. Due to the small valence band offset, a magnetic f ield-induced type I to type II transition occurs for the heavy-hole st ate. We show that the main contribution to this transition comes from the excitonic effects, which nearly compensate for the large decrease of the confinement energy. In wide quantum wells with high manganese c ontent we found an enhanced paramagnetic exchange interaction, which i s discussed in terms of interface effects.