The theory of the electrical conductivity in alternating fields is developed for non-degenerate semiconductors with spherical energy surfaces As in the Drude-Zener theory, the conductivity is a complex quantity and the real and imaginary parts are derived as functions of frequency and of temperature.
The cases of lattice scattering and impurity scattering are investigated separately for single-band models and the results are applied to intrinsic semiconductors by considering the two-band model with lattice scattering, and to imputiyy semiconductors by combining the scattering mechanisms. The loss tangent is also calculated and a comparison is made with the available experimental data