Abstract:
The method aimed at calculation of the electronic structure of an atomic cluster embedded either in an ideal crystal or in an effective medium representing a random alloy is developed on the basis of the TB-LMTO scheme. We discuss the construction of embedding potentials, the correct treatment of electrostatic interactions of the cluster with the surrounding medium, and the calculation of cluster energies. We derive the corrections to the band energy of a cluster. The method makes possible to determine the electronic structure (charge distribution, local densities of states) and magnetic properties of the cluster and to extract impurity formation energies, effective interactions between atoms and between magnetic moments. As an illustration, the method is applied to studies of magnetism of non-magnetic defects in oxides, to calculations of the formation energies for impurities in a metal host and to determination of parameters of Bruno, Zingales and Wang model of charge transfer and screening in metallic alloys.