Free Carrier Magneto‐Optical Effects in the Reststrahlen Region of n‐PbTe

Magnetoreflection spectra of n‐PbTe in the wave‐number region 20 to 200 cm−l are measured with magnetic fields up to 16 T. The PbTe expitaxial films grown on BaF2 and NaCl substrates have rarrier concentrations between 6 × 1016 and 5 × 1017 cm−3. For the PbTe a model‐dielectric function according to Wallace is used, including frequency and magnetic field dependences of the carrier damping and the effective masses. For small magnetic fields the nonparabolicity of the conduction band can be described by a two‐band Kane model. At higher magnetic fields the influence of polaron coupling is observed.