Covalent interactions in alloys of transition metals with simple metals or metalloids

Abstract
The covalent interaction between localized transition metal d states and extended metalloid sp states, which plays an important role in the formation of alloys of transition metals with simple metals or metalloids, is considered from the point of view of the Anderson impurity model. The authors demonstrate how by means of concepts derived from this impurity model a basic understanding of the electronic structure of transition metal-metalloid alloys can be obtained. In addition, the experimental investigation of the electronic structure of such compounds by means of high-energy spectroscopies is discussed. In particular, they consider the interpretation of experimental results from photoelectron spectroscopy and X-ray absorption spectroscopy.