The band structure of semimagnetic Hg1−yMnyTe/Hg1−xCdxTe type-III quantum wells has been calculated using eight-band k · p model in an envelope function approach. Details of the band structure calculations are given for the Mn free case (y = 0). A mean field approach is used to take the influence of the sp − d exchange interaction on the band structure of QW's with low Mn concentrations into account. The calculated Landau level fan diagram and the density of states of a Hg0.98Mn0.02Te/Hg0.3Cd0.7Te QW are in good agreement with recent experimental transport observations. The model can be used to interpret the mutual influence of the two-dimensional confinement and the sp−d exchange interaction on the transport properties of Hg1−yMnyTe/Hg1−xCdxTe QW's.

We report resonant spin-flip Raman scattering measurements in CdTe/Cd 1Ϫx Mg x Te single quantum wells with xϭ0.15, 0.26, and 0.5 as well as in Cd 1Ϫx Mg x Te alloys with xϭ0, 0.15, and 0.5. Effective g factors of electrons and heavy holes are measured as a function of the quantum well width (18Ϫ100 Å͒ and the angle of the magnetic field with respect to the growth axis. The electron g factors in quantum wells are between the values for bulk CdTe (g e ϭϪ1.644Ϯ0.005) and Cd 0.85 Mg 0.15 Te (g e ϭϪ0.802Ϯ0.005). We show that the change in the energy gap induced by the quantum confinement of the carriers provides the dominant contribution to the electron g factor in quantum wells. A large g factor anisotropy for conduction electrons is observed. It is shown that this anisotropy depends on the splitting between light-and heavy-hole states. The experimentally determined g factors are in good agreement with theoretical predictions. ͓S0163-1829͑97͒06128-6͔

Quasi-zero-dimensional magnetic polarons in single Cd 0.93 Mn 0.07 Te/Cd 0.6 Mg 0.4 Te quantum dots have been studied by photoluminescence spectroscopy. By comparing the experimental data with model calculations, the energy, the internal magnetic field, and the volume of the magnetic polarons are obtained. Moreover, the magnetic environment of the recombining electron hole pair causes a distinct broadening of the emission line (ϳ4 meV) of one diluted magnetic single quantum dot. The alignment of the Mn-spins in high magnetic fields results in a linewidth narrowing of almost one order of magnitude and the linewidth becomes comparable to that of a nonmagnetic Cd 0.93 Mg 0.07 Te/Cd 0.6 Mg 0.4 Te reference sample. RAPID COMMUNICATIONS R7768PRB 62 A. A. MAKSIMOV et al. RAPID COMMUNICATIONS R7770PRB 62 A. A. MAKSIMOV et al.

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