Search academic texts

Information × Registration Number 0222U000649, 0119U100673 , R & D reports Title Optical properties of crystal nanostructured and defect materials popup.stage_title Head Yanovskyi Volodymyr V., Доктор фізико-математичних наук Registration Date 14-01-2022 Organization Institute of Single Crystals of the National Academy of Sciences of Ukraine popup.description2  The study of fundamental regularities related to the presence of impurity defective structures in common optical crystalline materials and defective structures of nano- and meta-dimensional materials has been performed. A nonperturbative approach has been developed to study the nonlinear response of multilayer graphene to a high-frequency electromagnetic field. A phase transition to the "supersolid" state in a dilute two-dimensional gas of electron-hole pairs with spatially separated components has been revealed. The intensities of the third harmonic generation and photoconductivity for three-layer ABC-graphene were determined. The general theory of diffusion evolution of gas-filled pores in nano- and meso-particles is constructed. The relaxation of the internal gas pore was investigated by the method of molecular dynamics, which allowed to take into account the discrete internal structure of the particle. It is proved that the nature of pore relaxation is determined by the initial phase state of the cluster. It was found that inside solid clusters there are "magic" pores that do not disappear during the entire simulation time. Qualitative differences between these approaches and the modes in which they are consistent have been identified. It is proved that in order to increase the share of titanium in the Ti3+ state, the crystal must be grown under reducing conditions. Under oxidizing conditions, titanium in the Ti4 + state predominates, a significant proportion forming double and triple complexes with aluminum vacancies. Under reducing conditions, titanium in the Ti3+ state and Ti3+ - Ti4+ vapors predominate. A relation is obtained that describes the relationship between the concentrations of simple and complex defects. According to the results of research, the conditions under which the optical quality of such an important crystal as Ti: sapphire can be improved are determined. Product Description popup.authors Brodskii Roman Yevgenyevich Hermash Kostiantyn Volodymyrovych Kopp Mihail I, Kravchenko Lyudmila Yu Kulik Konstantin M Kulik Tatyayna V Maslovsky Yuri Mykolayovych Naplekov Dmitry Mihailovich Ratner Maryna Anatoliyivna Fil Dmytro V. Schirova Nataliya V Yanovskyi Volodymyr V popup.nrat_date 2022-03-09 Close