title: Anomalous duality of 4f electrons in filled skutterudite CeOs4Sb12.
abstract: We study the electronic structure of the filled skutterudite CeOs4Sb12 using photoemission spectroscopy (PES). Soft x-ray excited Ce 3d-4f resonant PES confirms the existence of Ce 4f states at the Fermi level (EF). Temperature dependent high-resolution laser-PES spectra reveal a pseudogap formation around EF, which can be explained in terms of the hybridization gap. Simultaneously, a sharp feature is formed just above EF with decreasing temperature. The heavy-fermion-like specific heat is attributed to the occupation of this feature. The results identify the origin of the anomalous coexistence of heavy-fermion and pseudogap behavior in terms of a symmetry dependent hybridization.
authors.affiliation: RIKEN SPring-8 Center, Sayo-gun, Hyogo 679-5148, Japan. matunami@spring8.or.jp
authors.forename: M
authors.initials: M
authors.lastname: Matsunami
authors.forename: R
authors.initials: R
authors.lastname: Eguchi
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authors.initials: T
authors.lastname: Kiss
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authors.lastname: Horiba
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authors.lastname: Chainani
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authors.lastname: Taguchi
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authors.lastname: Yamamoto
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authors.lastname: Togashi
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authors.lastname: Watanabe
authors.forename: X-Y
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authors.lastname: Wang
authors.forename: C-T
authors.initials: CT
authors.lastname: Chen
authors.forename: Y
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authors.lastname: Senba
authors.forename: H
authors.initials: H
authors.lastname: Ohashi
authors.forename: H
authors.initials: H
authors.lastname: Sugawara
authors.forename: H
authors.initials: H
authors.lastname: Sato
authors.forename: H
authors.initials: H
authors.lastname: Harima
authors.forename: S
authors.initials: S
authors.lastname: Shin