Rizak I. Thermal and physical properties as well as transfer phenomena at thermal and photostructural transformations of chalcogenide ion ferroelectrics of hexaseleniumhypodiphosphate tin type and ion conductors of lithium tetraborate.

The thesis is devoted to the complex study of static, dynamic and kinetic properties at thermal photostructural transformations of ion ferroelectrics of hexaseleniumhypodiphosphate tin family and ion conductor of lithium tetraborate. For the first time in the physics of condensed systems the existence zone of Lifshitz tricritical point was estab-lished at T-p-y-x diagram of (PbySn1-y)2P2(SexS1-x)6 ion ferroelectrics. The features and common patterns of transport charge, impulse and heat in the chalcogenide ferroelectric semiconductor systems with structural phase transitions and lithium tetraborate were found. The algorithm and mathematical software to calculate the density of phonon states of solids depending on the specific heat with temperature were developed. The micro-scopic model of lattice instability and mechanism of photothermal and structural transfor-mations in the compounds studied were created using ab initio calculations of static and dynamic properties of lithium tetraborate ion conductors as well as ion ferroelectrics of hexatiohypodiphosphate tin type