SELF-CONSISTENT GREEN-FUNCTION METHOD FOR DISORDERED SURFACES

The electronic structure of disordered metal surfaces is calculated using a self-consistent Green's function technique based on the LDA and on the TB-LMTO-CPA method. The potentials are treated within the ASA, but for their construction both the monopole and dipole components of the charge density are used. This is necessary for accurate evaluation of the work functions. The method can describe various situations ranging from the ordered and disordered overlayer on the metal substrate to the surface of disordered alloy with compositional inhomogeneity close to surface. The parameters of effective Ising model for disordered surfaces axe calculated. They can be used in studies of segregation phenomena or surface phase diagrams. The theory is illustrated on the random AgPd overlayer on fcc(001) Ag, and on the fcc(001) face of random PdRh alloy.