TEMPERATURE-INDUCED INTRABAND TRANSITIONS IN THE N-TYPE HGTE/CDTE SUPERLATTICE

Far-infrared magneto-optical experiments have been performed on a n-type 90 - HgTe/40 - 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 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 40 meV. Calculations show that, for our particular layer thicknesses, the sample should be semimetallic for 350 meV where its linear in-plane energy dispersion gives very different magneto-optical behaviors from those for 40 meV. The successful fit of data for 40 meV, but the failure for 350 meV, provides evidence for a small valence-band offset in HgTe/CdTe superlattice. © 1990 The American Physical Society.