title: Evidence of a precursor superconducting phase at temperatures as high as 180 K in RBa2Cu3O(7-δ) (R=Y, Gd, Eu) superconducting crystals from infrared spectroscopy.
abstract: We show that a multilayer analysis of the infrared c-axis response of RBa2Cu3O(7-δ) (R=Y, Gd, Eu) provides important new information about the anomalous normal-state properties of underdoped cuprate high temperature superconductors. In addition to competing correlations which give rise to a pseudogap that depletes the low-energy electronic states below T*≫T(c), it enables us to identify the onset of a precursor superconducting state below T(ons)>T(c). We map out the doping phase diagram of T(ons) which reaches a maximum of 180 K at strong underdoping and present magnetic field dependent data which confirm our conclusions.
authors.affiliation: University of Fribourg, Department of Physics, Fribourg, Switzerland.
authors.forename: A
authors.initials: A
authors.lastname: Dubroka
authors.forename: M
authors.initials: M
authors.lastname: Rössle
authors.forename: K W
authors.initials: KW
authors.lastname: Kim
authors.forename: V K
authors.initials: VK
authors.lastname: Malik
authors.forename: D
authors.initials: D
authors.lastname: Munzar
authors.forename: D N
authors.initials: DN
authors.lastname: Basov
authors.forename: A A
authors.initials: AA
authors.lastname: Schafgans
authors.forename: S J
authors.initials: SJ
authors.lastname: Moon
authors.forename: C T
authors.initials: CT
authors.lastname: Lin
authors.forename: D
authors.initials: D
authors.lastname: Haug
authors.forename: V
authors.initials: V
authors.lastname: Hinkov
authors.forename: B
authors.initials: B
authors.lastname: Keimer
authors.forename: Th
authors.initials: T
authors.lastname: Wolf
authors.forename: J G
authors.initials: JG
authors.lastname: Storey
authors.forename: J L
authors.initials: JL
authors.lastname: Tallon
authors.forename: C
authors.initials: C
authors.lastname: Bernhard