First principles investigation of the structural, elastic, electronic and vibrational properties of vanadium-based V3X (X = Fe, Co, and Ni) compounds

The structural, elastic and related properties, electronic properties, thermodynamic, and vibrational properties of the V3X (X = Fe, Co, Ni) intermetallic compounds using the plane wave method within the density functional theory are studied and results are discussed in detail. There is a good agreement between the calculated lattice constants, formation enthalpies and available experimental and theoretical data. The band structure calculations predict that these compounds in the A15 phase show metallic features. Moreover, the studied compounds are highly anisotropic and ductile in nature. According to the calculated values of formation enthalpy, V-X and V-V bond lengths, electronic density of states at the Fermi level, and melting temperature, V3Co compound is more stable than other compounds. The elastic constants of these compounds and their related quantities such as bulk modulus (B), shear modulus (G), Cauchy pressure (C-P), B/G ratio, Young's modulus (E), Kleinman's parameter (zeta), elastic anisotropy (A), Poisson's ratio (nu), Lame's constants (lambda and mu), and Vicker's hardness (H-V) have been calculated using the Voigt-Reuss-Hill approximation. Besides, the anisotropic elastic properties are pictured in two and three-dimensional shapes (2D and 3D) for Young's modulus, linear compressibility, shear modulus, Poisson's ratio. It has been found that V3Fe, V3Co, and V3Ni compounds are vibrationally and mechanically stable.