Electronic structure of disordered overlayers on metal substrates

The electronic structure of a random overlayer on a nonrandom substrate, both consisting of transition-metal atoms, is determined theoretically by employing (i) the first-principles tight-binding linear-muffin-tin-orbital method to describe the band structure, (ii) the surface Green's function to treat the layered nature of the problem, and (iii) the coherent-potential approximation to include the influence of disorder in the overlayer. As an application we determine k?-resolved as well as k?-integrated layer-projected densities of states for the first few layers of a Ag(001) substrate coated with an overlayer of random Ag₇₅{Pd}₂₅$.