A theory of Fano effects in the electronic structure of d band metals and alloys

Abstract

The electronic structure of d band metals and alloys is studied by using the concept of the Fano effect which is commonly used in solid state optics. A simple theory based on the Anderson model is presented to explain the asymmetry in the local density of states (DOS) of s and p symmetry in a d band metal. A prescription is given for calculating the parameters in the Anderson model from first principles and some simple example calculations are carried out to illustrate AR. An antiresonance (AR) dip position in a local DOS at a given site is quite insensitive to a change in the potential at the site, while the d band at the surrounding sites is shifted due to the potential change. It is pointed out that this shift of the d band results in AR in a generalised phase shift Delta N_L, that is, a change in the number of occupied states due to the potential change. The significance of AR in Delta N_L in several phenomena is discussed.