D−centers in quantum wells: Spin-singlet and spin-triplet magneto-optical transitions

We consider the ground and excited states of ${\mathit{D}}^{\mathrm{-}}$ centers, i.e., neutral donors ${\mathit{D}}^0$ trapping an extra electron, in the spin-singlet and spin-triplet states in GaAs/${\mathrm{Ga}}_{1\mathrm{-}\mathit{x}}$ ${\mathrm{Al}}_{\mathit{x}}$As quantum wells (QW’s) in quantizing magnetic fields B>6 T. Taking into account the effects of band nonparabolicity and magnetopolaron corrections, we derive the energies of the dipole-allowed transitions and their line strengths. Very good agreement (e.g., within 1–3 ${\mathrm{cm}}^{\mathrm{-}1}$ below the region of the resonant magnetopolaron splittings) with the experimental data of Huant et al. for the singlet transitions is found.