Interparticle interaction in spin-aligned and spin-degenerate exciton systems and magnetoplasmas in II-VI quantum wells

Magnetoluminescence studies of highly excited undoped CdTe/${\mathrm{Cd}}_{0.88}$ ${\mathrm{Mn}}_{0.12}$Te and ${\mathrm{Cd}}_{0.97}$ ${\mathrm{Mn}}_{0.03}$Te/${\mathrm{Cd}}_{0.75}$ ${\mathrm{Mg}}_{0.25}$Te quantum wells (QW’s) have been carried out in magnetic fields up to 14 T at 4.2 K. Qualitatively different excitonic systems, spin aligned in (Cd,Mn)Te QW and spin depolarized in CdTe QW, have been generated. The interaction of spin-aligned excitons are found to be weakly repulsive. In contrast, an additional well pronounced emission line M has been found to appear at approximately 5 meV below the excitonic line in the spectra of the spin-degenerate system. This line is assigned to the emission of excitonic molecules consisting of excitons with different spins. Finally, we have shown that the renormalization of Landau-level transitions in dense electron-hole magnetoplasmas with several occupied Landau levels depends on their spin state, it is markedly weaker in the spin-polarized plasmas. © 1996 The American Physical Society.