Cyclotron resonance in 〈111〉-oriented InGaAs/AlGaAs strained layer superlattices

Strain-induced electric fields are known to occur in 〈111〉-oriented InGaAs/AlGaAs strained layer superlattices (SLS). These fields lead to interesting electro-optic behavior and changes in the confined subband structure. Cyclotron resonance (CR) in nominally undoped InGaAs/AlGaAs SLS reveals some complex features of the subbands that include absence of circular polarization selection rule, and an effective mass that depends on magnetic field and also on barrier composition. This behavior is attributed to the nature of the valence band states, and it is concluded that the CR is due to holes. These results support an earlier interpretation of interband and CR measurements in the same samples.