Hybridization Phenomena in Nearly-half-filled F-shell Electron Systems: Photoemission Study of EuNi2P2

The mixed-valent compound EuNi2P2 was studied by photoemission. Observed splittings and dispersions of the Eu 4f;{6} final state close to energy crossings of the Eu 4f and Ni 3d states are explained in terms of hybridization by a momentum and energy dependence of the electron hopping matrix element. These data obtained for a system with more than one 4f electron (hole) show that dispersions and hybridization gaps related to Kondo and heavy-fermion behavior can be found in other rare-earth-metal compounds apart from Ce and Yb-based ones.