title: Electronic screening-enhanced hole pairing in two-leg spin ladders studied by high-resolution resonant inelastic x-ray scattering at Cu M edges.
abstract: We study the electronic screening mechanisms of the effective Coulomb on-site repulsion in hole-doped Sr(14)Cu(24)O(41) compared to undoped La(6)Ca(8)Cu(24)O(41) using polarization dependent high-resolution resonant inelastic x-ray scattering at Cu M edges. By measuring the energy of the effective Coulomb on-site repulsion and the spin excitations, we estimate superexchange and hopping matrix element energies along rungs and legs, respectively. Interestingly, hole doping locally screens the Coulomb on-site repulsion reducing it by as much as 25%. We suggest that the increased ratio of the electronic kinetic to the electronic correlation energy contributes to the local superexchange mediated pairing between holes.
authors.affiliation: Institut für Angewandte Physik, Universität Hamburg, Jungiusstraße 11, D-20355 Hamburg, Germany and Center for Free Electron Laser Science (CFEL), Notkestraße 85, D-22607 Hamburg, Germany and NUSSNI-NanoCore, Department of Physics, National University of Singapore, Singapore 117542, Singapore and Singapore Synchrotron Light Source, National University of Singapore, Singapore 117603, Singapore.
authors.forename: A
authors.initials: A
authors.lastname: Rusydi
authors.affiliation: Institut für Angewandte Physik, Universität Hamburg, Jungiusstraße 11, D-20355 Hamburg, Germany and Center for Free Electron Laser Science (CFEL), Notkestraße 85, D-22607 Hamburg, Germany.
authors.forename: A
authors.initials: A
authors.lastname: Goos
authors.affiliation: Institut für Angewandte Physik, Universität Hamburg, Jungiusstraße 11, D-20355 Hamburg, Germany and Center for Free Electron Laser Science (CFEL), Notkestraße 85, D-22607 Hamburg, Germany.
authors.forename: S
authors.initials: S
authors.lastname: Binder
authors.affiliation: Institut für Angewandte Physik, Universität Hamburg, Jungiusstraße 11, D-20355 Hamburg, Germany and Center for Free Electron Laser Science (CFEL), Notkestraße 85, D-22607 Hamburg, Germany.
authors.forename: A
authors.initials: A
authors.lastname: Eich
authors.affiliation: Institut für Angewandte Physik, Universität Hamburg, Jungiusstraße 11, D-20355 Hamburg, Germany and Center for Free Electron Laser Science (CFEL), Notkestraße 85, D-22607 Hamburg, Germany.
authors.forename: K
authors.initials: K
authors.lastname: Botril
authors.affiliation: Physics Department and Frederick Seitz Materials Research Laboratory, University of Illinois, Urbana, Illinois 61801, USA.
authors.forename: P
authors.initials: P
authors.lastname: Abbamonte
authors.affiliation: Singapore Synchrotron Light Source, National University of Singapore, Singapore 117603, Singapore.
authors.forename: X
authors.initials: X
authors.lastname: Yu
authors.affiliation: NUSSNI-NanoCore, Department of Physics, National University of Singapore, Singapore 117542, Singapore and Singapore Synchrotron Light Source, National University of Singapore, Singapore 117603, Singapore.
authors.forename: M B H
authors.initials: MB
authors.lastname: Breese
authors.affiliation: Nanoelectronics Research Institute, AIST, 1-1-1 Central 2, Umezono, Tsukuba, Ibaraki 305-8568, Japan.
authors.forename: H
authors.initials: H
authors.lastname: Eisaki
authors.affiliation: Department of Superconductivity, University of Tokyo, Bunkyo-ku, Tokyo 113, Japan.
authors.forename: Y
authors.initials: Y
authors.lastname: Fujimaki
authors.affiliation: Department of Superconductivity, University of Tokyo, Bunkyo-ku, Tokyo 113, Japan.
authors.forename: S
authors.initials: S
authors.lastname: Uchida
authors.affiliation: Photon Science, DESY, Notkestraße 85, D-22607 Hamburg, Germany.
authors.forename: N
authors.initials: N
authors.lastname: Guerassimova
authors.affiliation: Photon Science, DESY, Notkestraße 85, D-22607 Hamburg, Germany.
authors.forename: R
authors.initials: R
authors.lastname: Treusch
authors.affiliation: Photon Science, DESY, Notkestraße 85, D-22607 Hamburg, Germany.
authors.forename: J
authors.initials: J
authors.lastname: Feldhaus
authors.affiliation: Advanced Photon Source, Argonne National Laboratory, Argonne, Illinois 60439, USA.
authors.forename: R
authors.initials: R
authors.lastname: Reininger
authors.affiliation: Physics Department and Frederick Seitz Materials Research Laboratory, University of Illinois, Urbana, Illinois 61801, USA.
authors.forename: M V
authors.initials: MV
authors.lastname: Klein
authors.affiliation: Institut für Angewandte Physik, Universität Hamburg, Jungiusstraße 11, D-20355 Hamburg, Germany and Center for Free Electron Laser Science (CFEL), Notkestraße 85, D-22607 Hamburg, Germany and NUSSNI-NanoCore, Department of Physics, National University of Singapore, Singapore 117542, Singapore.
authors.forename: M
authors.initials: M
authors.lastname: Rübhausen