Anomalous quantum Hall resistance in Al0.6Ga0.4As0.1Sb0.9/InAs quantum well with tunable carrier density

We have investigated magneto-resistance in InAs/Al0.6Ga0.4As0.1Sb0.9 quantum well (QW), where the lattice mismatch at the interface is less than 2 %. The carrier concentration can be tuned by using positive and negative persistent photoconductivity effect, selected by the wavelength lambda=1.6 mu m or 0.95 mu m) of illumination. The electrons and holes coexist in the QW structure, and the contribution of both carriers should be taken into account. The observed deviation of Hall plateaus from the quantized value can be understood by considering the carrier transport in both electron and hole edge channels, and the equilibrium of chemical potential at the all electrodes in the sample. The transport properties in quantum Hall regime measured in the samples with the QW thickness of 15, 50 and 150 nm are reported.