Local valence instabilities and mixing in rare-earth semiconducting compounds

Abstract

We present a perturbative model for the electronic structure of a mixed-valent cation in a semiconducting Rare-Earth (RE) compound. We study local valence instabilities by considering the competition between the promotion energy of an electron into ‘d’ levels and the available shake-down energy which arises from the electronic relaxation around the ‘f’ hole; then we express local Intermediate Valence (IV) in terms of fd hybridization and local fd Coulombic interaction.