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Information × Registration Number 0221U105945, 0121U111445 , R & D reports Title Quantum tunneling of vibrational excitations in thermal conductivity of crystalline and amorphous materials and composites popup.stage_title Head Kryvchikov Oleksandr I., Доктор фізико-математичних наук Registration Date 13-09-2021 Organization B. Verkin Institute for Low Temperature Physics and Engineering of the National Academy of Sciences of Ukraine popup.description2  A number of amorphous and crystalline substances were analyzed and it was found that the temperature dependence of both crystalline and amorphous solids agrees with the representation of their thermal conductivity as an additive sum of two contributions, where the first is associated with oscillatory excitations and the second – diffusion is corresponds to quantum tunneling between the paired energy states of oscillatory excitations. The temperature dependence of the thermal conductivity of the contribution of quantum tunneling in the case of a strongly anisotropic molecular crystal of parachloronitrobenzene has been established. The setup for measuring isochoric thermal conductivity was modernized: a high-pressure measuring cell was made, and its installation was performed; the automation of the setup was carried out. Measurement of isochoric thermal conductivity for the reference substance is performed. A theoretical analysis of the temperature dependence of the isochoric thermal conductivity of amorphous glycerol was performed. The contribution of quantum tunneling to isochoric thermal conductivity for this series of substances is analyzed. Information on the empirical universal temperature dependence of thermal conductivity of a number of crystalline and amorphous materials and composites is obtained. The research results were presented at international conferences and articles were published in high-ranking journals. The obtained results and information of the research results were popularized to the general public, including experts in physics of low temperatures and condensed matter. A platform was created to discuss and promote knowledge on the topic "Thermal conductivity of solids" in the framework of the international conference on the physics of condensed matter and low temperatures at FTINT. B.I. Verkin NAS of Ukraine. During the work of the section, 20 reports were presented, including the results of the work of 76 researchers. Product Description popup.authors popup.nrat_date 2021-09-13 Close