REFORMULATION OF THE KORRINGA-KOHN-ROSTOKER COHERENT-POTENTIAL APPROXIMATION FOR THE TREATMENT OF SPACE-FILLING CELL POTENTIALS AND CHARGE-TRANSFER EFFECTS

We present a reformulation of the Korringa-Kohn-Rostoker (KKR) coheren t-potential approximation (CPA) which affords a number of conceptual a nd practical advantages over conventional formulations of the theory. In particular, as presented here the method can facilitate application to systems that cannot be described properly by a muffin-tin approxim ation to the cell potential and require a full potential treatment. Al so, the formalism allows the derivation of the KKR CPA self-consistenc y condition within both a scattering matrix and a Green function appro ach, leading to uniquely defined species-resolved charge densities and densities of states. As shown in a companion paper, this formulation also allows the treatment of the so-called charge-transfer effects ass ociated with Wigner-Seitz cells in an alloy which contain net amounts of charge.