The pressure effect on optoelectronic and mechanical properties of chalcopyrite BeSiN2


Ciftci Y., Alp İ.

MATERIALS TODAY COMMUNICATIONS, vol.24, 2020 (SCI-Expanded) identifier identifier

Abstract

The most significant physical properties under pressure are investigated for BeSiN2 compound through the density functional theory (DFT). It is found that all parameters computed within the generalized gradient theory (GGA-PBE) are compatible with the other related theoretical research outcomes. The equilibrium structural parameters are calculated using the full-optimization results and the obtained elastic data prove that BeSiN2 is mechanically stable. Furthermore, the pressure effects on mechanical properties of this chalcopyrite structure are presented. The value of bulk to shear modulus ratio for BeSiN2 reveals that this compound should be considered as a brittle material. The elastic anisotropy of Young modulus and Poisson ratio in 2D and 3D under pressure are also studied. Then, the density of states (DOS) and charge density map in direction (110) are visualized to examine the electronic characteristics in addition to the band structure analysis. It is predicted that BeSiN2 is a semiconductor, which has the direct band gap of 3.52 eV. The plotted phonon dispersion curves of BeSiN2 have no significant imaginary branches throughout the phonon spectrum. The optical properties (i.e. electron energy loss, reflectivity, extinction coefficient, and refractive index) are discussed besides the dielectric functions for the 0-30 eV energy range. It is concluded that BeSiN2 is suitable for optoelectronic applications since having an optical polarization anisotropy.