A Model of Valence Fluctuating Systems of Metallic Rare-Earth Compounds

Abstract

A possibility is pointed out that two or more than two conduction bands play a role in metallic valence fluctuating systems; the dispersion relations of the conduction bands have the same sign of tangent in the proposed model. The separation between conduction bands is one of essential parameters characterizing the system; the effective mass of quasi-particles is an increasing function of the separation. A possibility is discussed that the density of states has a camel back structure around the chemical potential. There is also a peak around unrenormalized f levels. The effect of dilution of f sites, for example, the replacement of Ce atoms by La ones, on the resistivity is investigated. The residual resistivity is higher, as the separation between conduction bands is larger.