Electronic states near the Fermi edge of YbInCu 4

Abstract

High-resolution low-energy excited photoemission spectra of YbInCu 4 with a first-order valence transition at T V∼42 K have been measured. In the spectra taken at hν =7 eV, the hybridization between the conduction-band and Yb 4f states is observed as a structure at ∼47 meV below the Fermi level and drastically increases at T V with decreasing temperature.