Analytic expressions for the high-frequency conductivity tensor and the absorption coefficient of a
weak electromagnetic wave due to free carriers for the case of electron-optical phonon scattering in doped
superlattices are calculated by using the Kubo-Mori method in two cases: the absence of a magnetic field
and the presence of a magnetic field applied perpendicular to the barriers. In comparison with normal
semiconductors, different dependence of the high-frequency conductivity tensor and the absorption
coefficients on the electromagnetic wave frequency ??, the temperature T of the system, the cyclotron
frequency ?? (when a magnetic field is present), and characteristic parameters of a doping superlattice is
obtained. The analytic expressions are numerically evaluated, plotted, and discussed for a specific doping of
the n-GaAs/ p-GaAs superlattice.
