Temperature-induced intraband transitions in then-type HgTe/CdTe superlattice

Abstract

Far-infrared magneto-optical experiments have been performed on a n-type 90-Å-HgTe/40-Å-CdTe superlattice. We have observed three electron cyclotron resonances which are remarkably resolved by increasing temperature. Through the studies of selection rules, temperature effects and k⋅p band calculations, they have been identified as three inter-Landau level transitions occurring in an electronic subband c1 for the value of — valence-band offset — Λ≃40 meV. Calculations show that, for our particular layer thicknesses, the sample should be semimetallic for Λ≃350 meV where its linear in-plane energy dispersion gives very different magneto-optical behaviors from those for Λ≃40 meV. The successful fit of data for Λ≃40 meV, but the failure for Λ≃350 meV, provides evidence for a small valence-band offset in HgTe/CdTe superlattice.