Systematics for trivalent and divalent rare-earth sulphides

摘要

The electronic structures of the rare-earth monosulphides are calculated with the self-interaction corrected local-spin-density approximation. This scheme allows part of the rare-earth f shell to be localized. Both trivalent and divalent configurations of the rare earths are considered, and the systematics in lattice constants and electronic densities of states are investigated. The scheme is found to be accurate in describing the properties of these systems and reveals that two kinds of f electrons in fact are present in the rare-earth monosulphides, namely both localized atomic-like f electrons and itinerant band f electrons, which hybridize with the normal conduction bands. The stability of the divalent configuration directly correlates with the number of band f electrons. [References: 10]