Influence of polymorphism of acentric ferroelastic solid-state structures on the propagation of sub-mm waves

Ferroelastic solid-state structures belong to the most perspective materials of SubMM electronics. The exclusive position of these materials is determined by three circumstances. First, behaviour of ferroelastic solid-state structures in the SubMM wave range is not determined by a response of an electronic subsystem. The interaction of the SubMM wave with the solid is determined by an ionic bulk of the crystal lattice. Second, the frequencies of oscillatory eigenmodes of ferroelastic structural units correspond to the SubMM range of waves. Third, ferroelastic compounds are polymorphous, therefore they display extremely high sensitivity of their eigenmodes to small variations of temperature in the vicinity of polymorphic transformation. Due to these facts dielectric properties of such materials on a fixed frequency can vary over a wide range at the expense of controlled variation of temperature T in the vicinity of its critical value T_c. The subject of the present work is the influence of polymorphism of ferroelastic solid-state structures on propagation of SubMM waves