Microwave induced Shubnikov–de Hass-type oscillation in InGaAs/InAlAs heterostructures

Microwave photoconductivity measurements of InGaAs/InAlAs and GaAs/AlGaAs heterostructures were carried out to investigate electronic spin states. In far-infrared magneto-optical absorption measurement, we confirmed a zero-field spin-splitting energy of the InGaAs/InAlAs heterostructure is 9 meV. In microwave modulated photoconductivity measurements, Shubnikov–de Haas oscillation was observed with quite high sensitivity. The energy of the sample was also determined from the oscillation. A dip structure was observed near cyclotron resonance field. By comparing with the result in GaAs/AlGaAs heterostructures and considering the heating effect by microwave irradiation, the origin of the Shubnikov–de Haas-type oscillation and the appearing dip structure are discussed.