Magnetotransport properties ofp-type HgTe-CdTe superlattices

Magnetotransport measurements are reported on HgTe-CdTe and ${\mathrm{Hg}}_{1-x}{\mathrm{Cd}}_x\mathrm{Te}-\mathrm{CdTe}$ superlatices. The Hall coefficients of these superlattices change from negative to positive as temperatures decrease and magnetic fields increase. Shubnikov-de Haas oscillations are observed and the temperature dependence of the amplitude of such oscillations indicates that the dominating carriers at low temperatures are the heavy holes. This is in agreement with band-structure calculations of these superlattices. The mobilities of these $p$-type superlattices are much higher than those of the best bulk $p$-type ${\mathrm{Hg}}_{1-x}{\mathrm{Cd}}_x\mathrm{Te}$ layers. We speculate that this mobility enhancement is related to the interface states which only exist in type-III superlattices.