Electronic structure and phase stability of A3Ti (A=Fe, Co, Ni, and Cu)

The electronic structure and cohesive properties (including equilibrium lattice constant, bulk modulus, and formation energy) of the intermetallic compounds A3Ti (A=Fe, Co, Ni, and Cu) in their L12, D024, and D022 structures have been studied by means of the self-consistent total-energy linear-muffin-tin-orbital method based on the local-density approximation. The correct phase preference (or stability) of these compounds is obtained. The correlation between the electronic concentration ce (defined as the number of electrons per atom) and the crystal structure found by Beck, Sinha, and Liu can be interpreted in terms of the filling of bonding states in a specific structure showing that the structural stability of A3Ti is predominantly governed by its electron packing in reciprocal space.