ABSTRACT
First-principles description of the electronic structure and properties of disordered alloys has been a challenging problem. The absence of translational symmetry is the main obstacle in the construction of a quantitative theory comparable in accuracy and efficiency with those for crystalline solids, based on the Bloch theorem and standard band structure methods. The mean-field approaches like the coherent potential approximation (CPA) overcome these difficulties by rein troducing a translationally-symmetric effective Hamiltonian. However, whenever local environment effects become important: like short-ranged ordering, chemicalaffinity-driven local clustering, or if we are dealing with rough surfaces and interfaces, the augmented space recursion is one of the more powerful techniques available to us. In this chapter, we will illustrate the application of the method and its suitability in different situations.
