HIGH-RESOLUTION PHOTOEMISSION-STUDY OF CERU2 - THE DUAL CHARACTER OF 4F ELECTRONS

High-resolution low-temperature photoemission spectroscopy was perform ed for CeRu2 to study the nature of low-lying excitations around the F ermi level (E(F)). It was found that the photoemission spectrum near E (F) shows two well-resolved peaks at and about 270 meV below E(F), whi ch are ascribed to the tail of the Ce 4 f(1) final state located just above E(F) and its spin-orbit satellite (Delta(SO)similar to 270 meV), respectively. This suggests that the many-body-correlation effect is necessary for understanding the electronic structure near E(F) of CeRu 2, although the Ce 4f electron exhibits a substantially itinerant char acter through the strong hybridization with the conduction electrons.