title: Coherent d-wave superconducting gap in underdoped La2-xSrxCuO4 by angle-resolved photoemission spectroscopy.
abstract: We present angle-resolved photoemission spectroscopy data on moderately underdoped La1.855Sr0.145CuO4 at temperatures below and above the superconducting transition temperature. Unlike previous studies of this material, we observe sharp spectral peaks along the entire underlying Fermi surface in the superconducting state. These peaks trace out an energy gap that follows a simple d-wave form, with a maximum superconducting gap of 14 meV. Our results are consistent with a single gap picture for the cuprates. Furthermore our data on the even more underdoped sample La1.895Sr0.105CuO4 also show sharp spectral peaks, even at the antinode, with a maximum superconducting gap of 26 meV.
authors.affiliation: Swiss Light Source, Paul Scherrer Institute, CH-5232 Villigen PSI, Switzerland.
authors.forename: M
authors.initials: M
authors.lastname: Shi
authors.forename: J
authors.initials: J
authors.lastname: Chang
authors.forename: S
authors.initials: S
authors.lastname: Pailhés
authors.forename: M R
authors.initials: MR
authors.lastname: Norman
authors.forename: J C
authors.initials: JC
authors.lastname: Campuzano
authors.forename: M
authors.initials: M
authors.lastname: Månsson
authors.forename: T
authors.initials: T
authors.lastname: Claesson
authors.forename: O
authors.initials: O
authors.lastname: Tjernberg
authors.forename: A
authors.initials: A
authors.lastname: Bendounan
authors.forename: L
authors.initials: L
authors.lastname: Patthey
authors.forename: N
authors.initials: N
authors.lastname: Momono
authors.forename: M
authors.initials: M
authors.lastname: Oda
authors.forename: M
authors.initials: M
authors.lastname: Ido
authors.forename: C
authors.initials: C
authors.lastname: Mudry
authors.forename: J
authors.initials: J
authors.lastname: Mesot