Hybridization Phenomena in Nearly-Half-Filledf-Shell Electron Systems: Photoemission Study ofEuNi2P2

Abstract

The mixed-valent compound ${\mathrm{EuNi}}_2{\mathrm{P}}_2$ 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.