PHONON ASSISTED TRANSITIONS IN THE FREE CARRIER ABSORPTION OF SEMICONDUCTORS IN QUANTIZING MAGNETIC FIELDS

We have investigated the effect of the scattering of free carriers in semiconductors by both acoustic and optical phonons on the free carrier absorption in quantizing magnetic fields. We find that for electromagnetic radiation polarized either parallel or perpendicular to the magnetic field, the free carrier absorption is an oscillatory function of the magnetic field. The origin of this oscillatory magneto-absorption is due to phonon assisted transitions between the various Landau levels of the free carriers in quantizing magnetic fields. From the periods of the oscillations in the free carrier absorption, the frequencies of those phonons which interact most strongly with the free carriers can be found