| Abstract |
A unified approach to the study of alloys, using the Korringa-Kohn-Rostoker (KKR) formulation based on atomic sphere approximation (ASA) and coherent-potential approximation (CPA), which allows the treatment of the disordered alloys and ordered alloys on an equal footing is presented. Some of the improvements afforded by the present approach over other methods for calculating the electronic structure of alloys are the following: (i) It allows the calculations of total energies, equilibrium lattice parameters, and other quantities for both the disordered alloys and selected ordered structures, since in either case the treatment of the Hamiltonian within CPA is the same. (ii) It allows incorporation of charge-transfer effects, for instance, by varying the volume of the atomic sphere associated with each species in the alloy so that each atom is individually charge neutral. (iii) It allows, for the first time, the calculations of non-spherical charge density of the disordered alloys. In conjunction with the generalized perturbation method (GPM) in the ASA, the present approach provides an accurate and reliable way of studying phase stability and ordering tendencies of alloys at T = 0K. The effective cluster interactions obtained from the GPM method can then be used in the cluster variation method for calculating the phase diagrams of alloys from first-principles. |
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