Cyclotron Absorption in Lead Telluride

Microwave absorption has been observed in n and p -type lead telluride as a function of static magnetic field at 1.8°K and 70 kMc/sec. Magnetic field B used in most cases was parallel to the sample surface. The derivative d P / d B of microwave absorption versus B was measured as a function of crystal orientation. The anisotropy of the effective mass of electrons is similar to that of holes in the (100) plane. The modes of microwaves are investigated in the high density plasma whose Fermi surface is assumed to be [111] prolate spheroids. A close fit to the experimental data is obtained from theoretical calculation with the values of the transverse mass m t =0.024 m 0 , 0.030 m 0 and the mass ratio m l / m t = K =10, 13 for electrons and holes respectively.