Quantized Hall effect and weak localization effects in two-dimensional HgTe–CdTe superlattices

Abstract

Electronic transport in the two-dimensional gas formed in superlattices of HgTe–CdTe has been investigated in both the weak-field (B<4 mT) and the intense-field regime (up to 29 T). We find that in high-mobility samples (53 000 cm2/V s) coherent backscattering effects (weak localization) are easily observable in the first regime while in the second regime quantized Hall steps are obtained in the same sample. The weak localization results have been exploited to obtain the temperature dependence of the electron dephasing rate and the spin–orbit scattering rate. Unlike AlGaAs–GaAs and Si–metal–oxide semiconductor field-effect transistor systems the spin–orbit scattering rate is very large (0.6 times the elastic scattering rate.) The quantized Hall-effect data are complicated by three factors which we discuss. These complications prevent an unambiguous interpretation at present, although differences from the AlGaAs–GaAs superlattice results are observed.