Theory of crystal-field splitting and orbit-lattice coupling of rare-earth impurities in noble metals

Abstract

The origin of the 4f state splitting of rare-earth ion in noble metals (Cu, Ag and Au) has been investigated. The contributions to the crystal-field and orbit-lattice coupling parameters from, (i) the potential of host ions screened by the conduction electrons, (ii) the screening effects due to the local 5d density, and (iii) the covalent mixing of the 4f and 5d states with the s and d bands have been calculated. As a result, good agreement with experimental values of the interaction parameters was obtained for the whole of the noble-metal series. The possibilities of different experimental techniques for unambiguous determination of the crystal-field parameters have also been discussed.