Conductivity of nonmetalic materials at submillimeter waves

Abstract

In contrast to normal metals, the fundamental dielectric dispersion in semi-conductors and superionic conductors takes place at rather low frequencies, 10 11 -10 12 Hz. The main changes in the spectra of superconductors during the superconducting phase transition also occur in the same frequency interval . On the base of systematic experimental study of submillimeter spectra of a variety of materials the general features of temperature behaviour of conductivity and dielectric permittivity of nonconventional conductors are analysed. The phenomenologycal model for describing the evolution of conductivity and dielectric permittivity spectra during the transition from free motion of charge carriers to their localization is developed. The high sensitivity of the submillimeter dielectric measurements for determination of the charge carriers characteristics in semiconductors and ionic conductors and for testing the quality of conventional and high-temperature superconductors is demonstrated.