Optical and magnetotransport properties of semimetallic InAs/(In,Ga)Sb superlattices

Abstract

Semimetallic superlattices and double heterojunctions of the system InAs/ In x Ga 1− x Sb have been studied by cyclotron resonance and magnetotransport in the magnetic field range 10–100 T. The cyclotron resonance is used to show that there is a magnetic field induced transition from semimetallic to semiconducting behaviour, at which almost all the carriers in the system disappear. The magnetotransport shows that large oscillatory Hall voltages occur in the quantised regime, and these are strongly temperature dependent. The field positions of the Hall resistivity peaks are related to the crossing of the electron and hole Landau levels. Hydrostatic pressure is used to achieve a controlled decrease of the band overlap, and to show that the Hall peaks and minima move to zero field as the zero overlap condition is approached. Both the cyclotron resonance and the magnetotransport show that the magnitude of the band overlap is orientation. dependent, being ≈ 60 meV larger for (1 1 1) oriented structures. This is attributed to the presence of a large interface dipole for this orientation.