title: Photoemission spectroscopic evidence of gap anisotropy in an f-electron superconductor.
abstract: We used low-temperature ultrahigh-resolution (360 microeV) photoemission spectroscopy with a laser as a photon source (Laser-PES) to study the superconducting (SC) gap of an f-electron superconductor CeRu2. The unique combination of the large escape depth expected from the known universal behavior and extremely high-energy resolution has enabled us to directly measure the bulk SC gap of an f-electron superconductor for the first time. The present study provides direct evidence for an anisotropic SC gap in CeRu2, and also demonstrates the potential of Laser-PES in investigating unconventional superconductivity realized in correlated d- and f-electron superconductors.
authors.affiliation: Institute for Solid State Physics (ISSP), University of Tokyo, Kashiwa, Chiba 277-8581, Japan.
authors.forename: T
authors.initials: T
authors.lastname: Kiss
authors.forename: F
authors.initials: F
authors.lastname: Kanetaka
authors.forename: T
authors.initials: T
authors.lastname: Yokoya
authors.forename: T
authors.initials: T
authors.lastname: Shimojima
authors.forename: K
authors.initials: K
authors.lastname: Kanai
authors.forename: S
authors.initials: S
authors.lastname: Shin
authors.forename: Y
authors.initials: Y
authors.lastname: Onuki
authors.forename: T
authors.initials: T
authors.lastname: Togashi
authors.forename: C
authors.initials: C
authors.lastname: Zhang
authors.forename: C T
authors.initials: CT
authors.lastname: Chen
authors.forename: S
authors.initials: S
authors.lastname: Watanabe