Localized character of 4f electrons in CeRhx (x=2,3) and CeNix (x=2,5)

Phys Rev Lett. 2003 Oct 10;91(15):157601. doi: 10.1103/PhysRevLett.91.157601. Epub 2003 Oct 10.

Abstract

We have measured Ce 4f spectral weights of extremely alpha-like Ce transition metal intermetallic compounds CeRhx (x=2,3) and CeNix (x=2,5) by using the bulk-sensitive resonant photoemission technique at the Ce M5(3d(5/2)-->4f) edge. High energy resolution and longer escape depth of photoemitted electron at this photon energy enabled us to distinguish the sharp Kondo resonance tails at the Fermi level, which can be well described by the Gunnarsson-Schönhammer calculation based on the Anderson impurity Hamiltonian. On the other hand, the itinerant 4f band description shows big discrepancies, which implies that Ce 4f electrons retain localized characters even in extremely alpha-like compounds.