First-principles predictions of electronic, elastic, and optical properties of ScBC and YBC ternary cermet phases. (September 2020) - Qu, Deyi
Abstract: In order to better understand the physical properties and provide theoretical support for the applications of ScBC and YBC ternary cermet phases, the electronic, elastic, optical and phonon properties of ScBC and YBC were calculated by the first-principles calculations. ScBC and YBC were thermodynamically and dynamically stable based on the formation enthalpies and phonon dispersions. The charge density difference and bond population showed that B-2 s, 2 p and C-2 s, 2 p states were hybridized to form stronger B–C covalent bonds in ScBC and YBC. The calculated elastic properties indicated that these ternary ceramic phases are brittle and elastic anisotropic with the elastically anisotropic order of ScBC > YBC. Finally, the optical properties, including the dielectric function, reflectivity and absorption coefficient, were investigated, and the results showed that YBC and ScBC have optical anisotropies. Highlights: B–C bonds are covalent, and TM-B/C bonds are covalent-ion mixed bonds. ScBC and YBC are elastically anisotropic. The optical anisotropy of YBC is higher than that of ScBC.