ELECTRONIC-STRUCTURE OF METALLIC ALLOYS USING CHARGE-NEUTRAL ATOMIC SPHERES

Based on the idea of charge-neutral atomic spheres we have calculated the electronic structure of ordered and disordered Cu-Zn, Ni-Pt, and Al-Li alloys using the linear-muffin-tin-orbital (LMTO) method and the Korringa-Kohn-Rostoker coherent potential approximation (KKR CPA) method in the atomic-sphere approximation (ASA), respectively. The equilibrium lattice constants and the formation energies of ordered alloys obtained with the LMTO-ASA method show that the calculations done with charge-neutral atomic spheres are closer to the experimental results than the conventional equivolume atomic-sphere-type calculations. In the case of disordered alloys, we find that charge-neutral atomic spheres are essential for the stability of these alloys within the KKR-ASA CPA method where the Madelung-type contribution is neglected. Our results clearly indicate that for disordered alloys any future implementation of a full-potential method within the single-site CPA should be carried out with charge-neutral cells rather than the Wigner-Seitz cells.