First-principles investigations on structural, elastic and mechanical properties of BNxAs1−x ternary alloys

Abstract

A systematic investigation of the structural optimization, elastic and mechanical properties of the BN[Formula: see text]As[Formula: see text] ternary alloys are reported in the present work using the density–functional theory with the generalized gradient approximation (GGA) of the exchange–correlation functional. Some of the constants which are used to analyze the properties including elastic constants and modulus, and some parameters describing the elastic anisotropy and Debye temperature are also calculated. Our calculations were performed to evaluate the equilibrium lattice constant and band structure compared with the available theoretical works. On the one hand, our results might be expected to provide a theoretical basis for future study of BN[Formula: see text]As[Formula: see text] alloys towards elastic or mechanical properties. On the other hand, we draw a conclusion that BN[Formula: see text]As[Formula: see text] alloys show direct bandgap when x equals 0.25, 0.5 or 0.75. We obtained the elastic modulus, Poisson’s ratio and universal anisotropic index which are used to demonstrate the elastic anisotropy of these alloys which is proved according to our calculations. Also, we calculated the Debye temperature to illustrate covalent interactions and obtained the lower limit of the thermal conductivity for further research.