Electronic Structure of 3d and 4d Impurities in Mo and Nb

Calculations are presented for the electronic structure of 3d and 4d‐ impurities in Mo and Nb. Using the density functional theory in the local spin density approximation of Barth and Hedin the electronic structure of the impurity is calculated by the KKR Green's function method. The impurity is described by a single perturbed muffin‐tin potential which is determined self‐consistently. In Nb and Mo 4d‐ impurities with the same excess valence Δ Z show very similar density of states. All 4d‐ impurities are unmagnetic. In Mo, of all 3d‐ impurities only Mn, Fe, and Co are magnetic. InNb, the formation of local moments of 3d‐ impurities is uncertain according to the present calculations. The occurrence of the local moments cannot be understood by the Friedel‐Anderson concept based on virtual bound states. Rather the simple “covalent model” of magnetism recently introduced by Williams et al. gives a reasonable description of the spin polarized densities of states.