Vacancies and magnetic impurities in transition metals

Abstract

During the past decade a great deal of progress in our theoretical understanding of the electronic structure of alloys has been made by flrst-principles calculations. On the one hand these calculations have become possible because of the development of density functional theory which reduces the many electron problem to the solution of one particle equations and on the other hand because of the development of efficient methods to treat these equations with the help of large electronic computers. Compared to ideal crystals for which conventional reciprocal k-space methods can be used~the calculations for disordered or diluted alloys are more difficult due to the lack of periodicity. Only recent real space Green function methods have led to such calculations. As one of the different techlques used to calculate the electronic structure of dilute alloys, in section 2 of this paper the Kohn-Korrlnga-Rostoker Green function (KKR-GF) method for isolated impurities is described. This method has originally been proposed by Dupree [i], Beeby [2] and others and has been used extensively by us for many calculations. As examples, in section 3 recent results for vacancies in transition metals are presented and in section 4 magnetic impurities are considered.