High pressure behaviour of elastic and mechanical properties of NiGa intermetallic compound

We have employed the density functional theory plane-wave pseudopotential method with local density approximation and generalized gradient approximation to investigate the structural, elastic and mechanical properties of the intermetallic compound NiGa. The calculated equilibrium lattice constant and bulk modulus are in good agreement with the experimental and other calculated values. According to our best knowledge, from the elastic constants, the bulk modulus B, anisotropy factor A, shear modulus G, the Young modulus E and the Poisson ratio σ for NiGa compound are obtained for the first time. By comparison, our results for the elastic constants C_{ij}, bulk modulus B, shear modulus G and the Young modulus E are as good as those of NiAl compound. The dependences of the elastic and mechanical parameters of NiGa compound on pressure were also investigated. It was found that the cubic NiGa compound is mechanically stable under pressure according to the elastic stability criteria up to 13 GPa, and it is not elastically isotropic. By analyzing the ratio (B/G), it was concluded that NiGa compound is ductile in nature