First-principles calculation of the hexagonal-closed-packed Ni75Ta25 metastable phase

The total energy and electronic structure of the hcp Ni,Ta-76(25), metastable phase have been obtained by the self-consistent discrete variational method and the local X alpha exchange approximation. The total energy of this phase was calculated as a function of lattice constant, a, for a fixed c/a of 1.63, which is determined experimentally. The predicted lattice constant, i.e., a=4.93 a.u. is very close to the experimental value of a=4.97 a.u. In addition, the density of states and bonding charge density were used to clarify the characteristics of bonding in this metastable crystalline phase. (C) 1996 American Institute of Physics.