Cyclotron-resonance experiments done in a novel superlattice, HgZnTe-CdTe, provide the first determination of the conduction-band dispersion in a type-III superlattice. The measured electron-mass anisotropy is strongly dependent on the CdTe layer thickness, in agreement with band-structure and Landau-level calculations. These calculations show also that the studied superlattices are semimetallic, consistent with the large valence-band offset (300 meV). Another cyclotron-resonance transition is observed, evidencing strongly the formation of a two-dimensional electron gas.

• Received 2 February 1989

DOI:https://doi.org/10.1103/PhysRevLett.62.2024