抄録
Absorption of microwave near the cyclotron resonance by free carriers in a strong magnetic field is treated quantum-mechanically on the assumption of elastic scattering by impurities and phonons. It is pointed out that the homogeneous broadening is determined by a relaxation time τc which is analogous to the transport relaxation time for dc conductivity and is generally equal neither to the life time of Landau levels nor to any kind of its mean value. The behavior of τc in the quantum limit is discussed for various mechanisms of scattering. For scattering by piezoelectric phonons at finite temperatures τc becomes finite although the life time of a Landau level vanishes in the second order perturbation.
