title: Fermi surface topology of Ca1.5Sr0.5RuO4 determined by angle-resolved photoelectron spectroscopy.
abstract: We report angle-resolved photoelectron spectroscopy results of the Fermi surface of Ca1.5Sr0.5RuO4, which is at the boundary of magnetic/orbital instability in the phase diagram of the Ca-substituted Sr ruthenates. Three t(2g) energy bands and the corresponding Fermi surface sheets are observed, which are also present in the Ca-free Sr2RuO4. We find that while the Fermi surface topology of the alpha,beta (d(yz,zx)) sheets remains almost the same in these two materials, the gamma (d(xy)) sheet exhibits a holelike Fermi surface in Ca1.5Sr0.5RuO4 in contrast to being electronlike in Sr2RuO4. Our observation of all three volume conserving Fermi surface sheets clearly demonstrates the absence of orbital-selective Mott transition, which was proposed theoretically to explain the unusual transport and magnetic properties in Ca1.5Sr0.5RuO4.
authors.affiliation: Department of Physics, Boston College, Chestnut Hill, Massachusetts 02467, USA.
authors.forename: S-C
authors.initials: SC
authors.lastname: Wang
authors.forename: H-B
authors.initials: HB
authors.lastname: Yang
authors.forename: A K P
authors.initials: AK
authors.lastname: Sekharan
authors.forename: S
authors.initials: S
authors.lastname: Souma
authors.forename: H
authors.initials: H
authors.lastname: Matsui
authors.forename: T
authors.initials: T
authors.lastname: Sato
authors.forename: T
authors.initials: T
authors.lastname: Takahashi
authors.forename: Chenxi
authors.initials: C
authors.lastname: Lu
authors.forename: Jiandi
authors.initials: J
authors.lastname: Zhang
authors.forename: R
authors.initials: R
authors.lastname: Jin
authors.forename: D
authors.initials: D
authors.lastname: Mandrus
authors.forename: E W
authors.initials: EW
authors.lastname: Plummer
authors.forename: Z
authors.initials: Z
authors.lastname: Wang
authors.forename: H
authors.initials: H
authors.lastname: Ding