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Information × Registration Number 0225U003292, (0124U004302) , R & D reports Title Layered ferroics MM'P₂S(Se)₆ with unique functional properties for nanoscale heterostructures. popup.stage_title Синтез сполук та вирощування монокристалів додаткових хімічних складів з системи MM'P2S(Se)6. Моделювання структурних фазових переходів, аналіз в наближенні середнього поля фазових діаграм і термодинамічних властивостей. Оптична спектроскопія кристалів системи MM'P2S(Se)6, дослідження температурної залежності діелектричних властивостей, спонтанної поляризації, іонної провідності. Модельний опис взаємозв’язку спонтанної поляризації та іонної провідності для кристалів MM'P2S(Se)6. Head Vysochanskyi Yulian M., Доктор фізико-математичних наук Registration Date 13-06-2025 Organization Uzhhorod National University State Higher Educational Institution popup.description1 The work involves a combination of technological, experimental and theoretical studies of phosphorus-containing chalcogenide van der Waals single crystals MM'P₂S(Se)₆ (M - Cu, Ag; M' - In, Bi) and heterostructures based on them. The electronic and phonon spectra of crystals, size effects in nanolayers and heterostructures, ferroelectric, semiconducting and thermodynamic properties will be studied. Spontaneous polarization switching kinetics and dielectric properties, ionic conductivity and resistive switching of layered CuInP₂S₆ crystals with chemically modified properties will be studied. The study of the synergy of thermally activated copper or silver cations and the anharmonic dynamics of indium or bismuth cations in the spontaneous dipole ordering and in the cation migration controlled by electric field pulses through the structural layers will facilitate the design of new electronic devices based on the connection between the ferroelectric properties and the ionic conductivity of nanoscale layered packages of CuInP₂S₆ or AgBiP₂Se₆ compounds. The results of the work will be the basis for the creation of functional elements of devices for efficient processing of dynamic information with high density, covering spatial and temporal aspects, which is important for machine vision systems. popup.description2 The spectrum of pseudospin fluctuations at different temperatures calculated within the framework of the quantum anharmonic oscillator model in the mean-field approximation is compared with the data of the lattice dynamics studies by micro-Raman spectroscopy of CuInP2S6 crystal and with the temperature dependence of thermodynamic properties, in particular, heat capacity and thermal conductivity. A new type of quasiparticles: flexo-phonons and flexo-ferrons arising from flexoelectric interaction were investigated on the example of a uniaxial high voltage ferrielectric CuInP2S6 with a multiwell structure of the free energy landscape. The first-principles calculations of the effect of hydrostatic pressure on the crystal structure, spatial distribution of electron density and specificity of chemical bonds, electronic and phonon spectra of CuInP2S6 crystal were performed. The peculiarities of the interaction of the translation vibrations of copper and indium cations with the internal deformation modes of (P2S6)4- anions and with the modes of relative displacement of the structural layers have been determined. The calculated lattice dynamics in the ground state, in combination with the simulation results when considering the crystal structure as a set of quantum anharmonic oscillators, allowed us to develop a description of the temperature and pressure dependence of the functional parameters of the CuInP2S6 ferrielectricity within the framework of the concept of the ferron.  Product Description popup.authors YEVYCH Ruslan M. HLUKhOV Kostiantyn Ye. Hryts Viacheslav Yu. Kohutych Anton A. Liubachko Vitalii Yu. Medulych Mykola M. Molnar Oleksandr O. Pohodin Artem I. Shender Iryna O. popup.nrat_date 2025-06-13 Close