Nanocomposites and nanomaterials

Computational investigation of atomic and electronic structures of phosphate-based crystal-glass composites
Chornii V.1,2, Boyko V.1, Nedilko S.G.2, Borysiuk V.2, Hizhnyi Yu.2, Zhydachevskyy Ya.3   
1National University of Life and Environmental Sciences of Ukraine. Geroiv Oborony st., 15, Kyiv-03041, Ukraine. 
E-mail: vchornii@gmail.com, vchornii@nubip.edu.ua. 
2 Taras Shevchenko National University of Kyiv, Volodymyrs’ka st., 60, Kyiv-01601, Ukraine.
3 Institute of Physics Polish Academy of Sciences, al. Lotników, 32/46, Warsaw, Poland.

The interphase layers greatly determine the physical characteristics of composite materials, particularly, such as nanostructured glass-ceramics. These characteristics are difficult to predict using only general knowledge about atoms, ions or molecules interactions. At the same time, the mutual diffusion of component atoms can be effectively modeled in the molecular dynamics (MD) calculations. The further electronic structure calculations for the obtained atomic structures allow obtaining relevant micro and macro-characteristics of such layers. 
In this work the computational studies of the atomic and electronic structures of glasses and crystal-glass interphases were carried out using Materials Studio 2019 software package [1]. Two types of composites were considered: a) KBi(MoO4)2 crystal - K2O-P2O5-MoO3-Bi2O3 glass; and b) K2Eu(PO4)(WO4) crystal - K2O-P2O5-WO3-V2O5 glass. The atomic structures of initial glasses and interphases were calculated by MD methods implemented in Amorphous Cell and Forcite programs. The electronic structure calculations were performed in the DFT approximation using the band-periodic plane wave pseudopotential method CASTEP for which the cells of smaller sizes were used. The key structure–properties relations in studied glasses and crystal-glass composites were clarified, in particular, dependence of the optical characteristics of composite materials on atomic and electronic structures of interphase layers. A possibility of "engineering" the physical properties of novel glass-ceramics was analyzed.
 
1.	BIOVIA, Dassault Systèmes, Materials Studio 2019 (version 19.1.0.5), San Diego: Dassault Systèmes, 2018.