Magnetoabsorption in InSb quantum-well heterostructures

Abstract

Spin-resolved cyclotron resonance is observed in InSb/AlInSb quantum-well heterostructures. Spin-resolved transitions are identified for fields greater than 2.2 T and confirmed by $\mathbf{k}\ensuremath{\cdot}\mathbf{p}$ modeling. The cyclotron effective mass is calculated for a range of fields up to 11.5 T and is indicative of the strong nonparabolicity in this material. Resonant coupling is observed between the ground and first occupied subbands for normal-incidence excitation. This is explained in the context of conduction band-valance band mixing due to the narrow bandgap. Further resonant coupling is observed via interaction with a hybrid intersubband plasmon-LO phonon mode. This allows a quantitative estimation of the subband spacing and of the electron-phonon interactions in the quantum well.