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Information × Registration Number 0218U000401, 0115U001092 , R & D reports Title Chalcogenide crystals of ferroics with different dimensions for bistable elements of electronics. popup.stage_title Head . Molnar Alexander Alexandrovich, Registration Date 29-01-2018 Organization State Higher Educational Institution "Uzhgorod National University" popup.description2 The dependences of the electronic and phonon spectra of Sn(Pb)2P2S(Se)6 crystals on the pressure (in the range of up to tens of GPa) are analyzed experimentally and on the basis of ab initio calculations, the characteristics of semiconductor-metal transitions for various structural phases are determined. The dependence of spontaneous polarization on pressure was calculated by the Berry phase method. The optical, dielectric, electro physical and thermoelectric properties of crystals were experimentally studied as a function of temperature and the effect of pressure on these properties was analyzed. The domain structure of the ferroelectric phases of Sn2P2S6 3D crystals and CuInP2S6 2D crystals is studied by observing the switching processes and hysteresis loops by using piezo-force microscopy. The observed temperature dependences of the domain structure with Monte Carlo simulation results are compared based on calculations from the first principles of the local three-well potential for fluctuations of the spontaneous polarization. According to the temperature dependence of the dielectric constant with different rates of temperature change (in the range 0.1 - 0.001 K min-1), effects of non-equilibrium effects were investigated. The dependence of the domain structure on the thickness of CuInP2S6 single-crystal plates is studied at its reduction to tens of nanometers. The role of ionic and semiconductor conductivity in screening of the depolarizing field of spontaneous polarization is studied. Product Description popup.authors Височанський Юліан Миронович Горват Андрій Андрійович Марковська Наталія Імрівна Молнар Олександр Олександрович Шпак Іван Іванович popup.nrat_date 2020-04-02 Close