Photoemission and BIS study of Ce 4Bi 3 and CeBi 0.7Te 0.3

Abstract

The electronic structures of Ce 4Bi 3 and CeBi 0.7Te 0.3 were studied by core-level X-ray photoelectron spectroscopy (XPS), valence band resonant photoemission using synchrotron radiation, and Bremsstrahlung Isochromat Spectroscopy (BIS). The 3 d core-level XPS shows that the valence of Ce ions is close to three in both compounds, and the effective hybridization between Ce 4 f level with valence electrons is stronger for CeBi 0.7Te 0.3 than Ce 4Bi 3. This is probably due to the stronger p- f mixing matrix element in CeBi 0.7Te 0.3 resulting from the shorter distance between Ce and Bi atoms. The density of states (DOS) near the Fermi level was also measured by the ultraviolet photoelectron spectroscopy and BIS, and it is found to be larger for Ce 4Bi 3 than CeBi 0.7Te 0.3. This difference comes about primarily because a larger number of extra electrons fill the Ce 5 d conduction band in Ce 4Bi 3.