Roles of the electrons-per-atom ratio on the structural stability of certain binary alloys

We report on the structural phase stability of certain binary alloys of less simple metals. The results show that the one-electron contribution arising from the virtual crystal approximation dominates the structural prediction for some of the phases observed in these systems. The neutral object contribution describing the residual interaction of the pseudo-atoms simply reflects the concentration behaviour of the one-electron contribution. The calculations re-emphasise that the first non-vanishing reciprocal lattice vectors and the diameter of the free electron Fermi sphere 2ksub(F) play a crucially important role on the structural energetics of the systems we consider. (author)