INFLUENCE OF THE KONDO-HOLE IMPURITIES ON THE ELECTRONIC-STRUCTURE OFCENISN AND CERHSB

The electronic structure of Ce1-xLaxNiSn and Ce1-xLaxRhSb has been stu died by photoelectron spectroscopy. The x-ray excited valence-band spe ctra are compared with ab initio electronic-structure calculations usi ng the linearized muffin-tin orbital method. The results have been use d to compare and contrast the effect of La substitution on the ground state properties of the Kondo insulators CeNiSn and CeRhSb. The Ce 3d x-ray photoemission spectroscopy spectra show evidence for the mixed v alence state of Ce in CeRhSb alloys, as also seen for CeNiSn, whereas the spectra for the La substituted (Ce,La)NiSn compounds show only evi dence for a purl Ce3+ ground state. We suggest the presence of Kondo-h ole states in Ce1-xLaxRhSb.