Shubnikov–de Haas and Hall oscillations in InAs-Ga1−xInxSb superlattices

We report a quantum transport investigation of n-type InAs-${\mathrm{Ga}}_{1\mathrm{-}\mathit{x}}$ ${\mathrm{In}}_{\mathit{x}}$Sb superlattices. Our data display Shubnikov–de Haas oscillations in the diagonal conductivity accompanied by plateaulike inflections in the Hall conductivity. Correlation of the oscillation periods with carrier densities obtained from mixed-conduction analyses of the nonoscillating conductivity components implies that the electron effective mass is nearly isotropic. Because of the large miniband width (>150 meV), one can rule out the conventional quantum Hall effect as the source of the structure in the Hall condutivity. It is instead attributed to a high density of localized states at the bottom of each Landau level, resulting from interface-roughness-induced potential fluctuations.