Electronic Structure of Magnetic Impurities in Copper

Abstract

A model is presented for dilute iron-series magnetic impurities in copper, which is a generalization of the work of Anderson and the work of Wolff taking into consideration the band structure of copper. The impurity virtual states are treated as bound states pushed out of the $3d$ bands of copper and broadened into virtual states by admixture with the conduction band. The copper energy bands are represented by an interpolation scheme developed by Hodges and Ehrenreich fit to the energy-band calculation done by Burdick. The equations of motion for the single-particle Green's function of the perturbed lattice are solved in the Hartree-Fock approximation using the Koster-Slater method, and from this Green's function the charge density is calculated and used to solve the equations of motion self-consistently. The bound states at or above the Fermi energy are found to be better than 95% localized to the impurity site, and therefore simplifications result from treating the problem in a hole formalism (i.e., the localized moment is attributed to unoccupied bound states at the impurity site). The effects of crystal-field splitting and spin-orbit coupling on the bound states are discussed. Bohr magneton numbers are calculated and found to be in agreement with experiment in most cases. The net polarization of the conduction bands is also discussed and found to agree semiquantitatively with experiment.