title: Hybridization gap in heavy fermion compounds.
abstract: We report the results of optical studies of new heavy fermion compounds YbFe(4)Sb(12) and CeRu(4)Sb(12). We show that these compounds, as well as several other heavy fermion materials with a nonmagnetic ground state, obey a universal scaling relationship between the quasiparticle effective mass m(*) and the magnitude of the energy gap Delta in the excitation spectrum. This result is in accord with the picture of hybridization of localized f-electron and free carrier states.
authors.affiliation: Department of Physics, University of California, San Diego, La Jolla, California 92093, USA.
authors.forename: S V
authors.initials: SV
authors.lastname: Dordevic
authors.forename: D N
authors.initials: DN
authors.lastname: Basov
authors.forename: N R
authors.initials: NR
authors.lastname: Dilley
authors.forename: E D
authors.initials: ED
authors.lastname: Bauer
authors.forename: M B
authors.initials: MB
authors.lastname: Maple