Impurity cyclotron resonance in InGaAs/AlAs superlattice under ultra high magnetic fields

We have carried out cyclotron resonance (CR) measurements of (InGaAs)8/(AlAs)8 superlattice (SL) to investigate electronic properties of the SL under pulsed ultra-high magnetic fields. The magnetic fields up to 160 T were generated by using the single-turn-coil technique. Clear CR signals were obtained in the transmission of far-infrared laser through the SL at room temperature and lower temperature. We observed a shift of CR peak to lower magnetic field caused by transition from free-electron CR to impurity CR below ∼90 K. Compared with the previous works of GaAs/AlAs SL, the peak shift was small and the transition temperature was low. This result suggests that a binding energy of the impurity in the InGaAs/AlAs SL is smaller than the GaAs/AlAs SL.