Intrasubband spin-flip relaxation by one-magnon processes in ${\mathrm{Cd}}_{1-x}{\mathrm{Mn}}_x\mathrm{Te}$ quantum wells

The $“s-d$ model” which contains a description of band electrons coupled to localized spins is used to calculate the intrasubband spin-flip lifetime due to scattering of electrons by magnons in ${\mathrm{Cd}}_{1-x}{\mathrm{Mn}}_x\mathrm{Te}$ quantum well structures. We found that the low-temperature result ${\tau }_{\mathrm{flip}}\approx 1\mathrm{ps}$ agrees nicely with the low-temperature time-resolved photoluminescence measurements. Furthermore, the spin-flip lifetime broadening was found to scale with $L^{-1},$ $L$ being the quantum well width.