title: The ground state of the pseudogap in cuprate superconductors.
abstract: We present studies of the electronic structure of La(2-x)BaxCuO4, a system where the superconductivity is strongly suppressed as static spin and charge orders or "stripes" develop near the doping level of x = (1/8). Using angle-resolved photoemission and scanning tunneling microscopy, we detect an energy gap at the Fermi surface with magnitude consistent with d-wave symmetry and with linear density of states, vanishing only at four nodal points, even when superconductivity disappears at x = (1/8). Thus, the nonsuperconducting, striped state at x = (1/8) is consistent with a phase-incoherent d-wave superconductor whose Cooper pairs form spin-charge-ordered structures instead of becoming superconducting.
authors.affiliation: Condensed Matter Physics and Materials Science Department, Brookhaven National Laboratory, Upton, NY 11973, USA. valla@bnl.gov
authors.forename: T
authors.initials: T
authors.lastname: Valla
authors.forename: A V
authors.initials: AV
authors.lastname: Fedorov
authors.forename: Jinho
authors.initials: J
authors.lastname: Lee
authors.forename: J C
authors.initials: JC
authors.lastname: Davis
authors.forename: G D
authors.initials: GD
authors.lastname: Gu