Magnetoabsorption in HgCdTe/CdHgTe Quantum Wells in Tilted Magnetic Fields

Absorption spectra in a 30-nm Hg$_{0.075}$Cd$_{0.925}$Te/Cd$_{0.74}$Hg$_{0.26}$Te quantum well in tilted magnetic fields up to 13 T have been studied. Energy spectra in the conduction band (in the absence of the normal field component), as well as electron Landau levels spectra in the presence of the magnetic field component in the quantum well plane, have been calculated within the eight-band Kane model. In classical magnetic fields, the broadening of cyclotron resonance lines has been detected; this broadening is due both to the removal of the Kramers degeneracy of the lower quantum-confinement subband and to difference of cyclotron masses in split subbands. The longitudinal field component in quantizing magnetic fields is responsible for the hybridization of Landau levels, which is enhanced with an increase in their energy (on the scale of the quantum confinement energy), manifested in the appearance of “forbidden” transitions in magnetoabsorption spectra.