Homogeneous linewidth of excitons in semimagnetic CdTe/Cd1−xMnxTe multiple quantum wells

We report on a detailed experimental study of the homogeneous linewidth of heavy-hole excitons in semimagnetic CdTe/${\mathrm{Cd}}_{1\mathrm{\ensuremath{-}}\mathit{x}}$${\mathrm{Mn}}_{\mathit{x}}$Te multiple quantum wells. Transient four-wave-mixing experiments are used to obtain the homogeneous linewidth by measuring the dephasing time of the excitons. We find a dephasing time of 2.2 ps corresponding to a homogeneous linewidth of 0.6 meV at low temperature and moderate exciton density. The homogeneous linewidth increases linearly with both exciton density and lattice temperature. The contributions of exciton\char21{}acoustic-phonon scattering, exciton-exciton interaction, and disorder to the homogeneous linewidth are determined.