title: Atomic scale real-space mapping of holes in YBa2Cu3O(6+δ).
abstract: The high-temperature superconductor YBa2Cu3O(6+δ) consists of two main structural units--a bilayer of CuO2 planes that are central to superconductivity and a CuO(2+δ) chain layer. Although the functional role of the planes and chains has long been established, most probes integrate over both, which makes it difficult to distinguish the contribution of each. Here we use electron energy loss spectroscopy to directly resolve the plane and chain contributions to the electronic structure in YBa2Cu3O6 and YBa2Cu3O7. We directly probe the charge transfer of holes from the chains to the planes as a function of oxygen content, and show that the change in orbital occupation of Cu is large in the chain layer but modest in CuO2 planes, with holes in the planes doped primarily into the O 2p states. These results provide direct insight into the local electronic structure and charge transfers in this important high-temperature superconductor.
authors.affiliation: 1] Department of Materials Science and Engineering, Brockhouse Institute and Canadian Centre for Electron Microscopy, McMaster University, 1280 Main Street West, Hamilton, Ontario, Canada L8S 4M1 [2].
authors.forename: N
authors.initials: N
authors.lastname: Gauquelin
authors.affiliation: Department of Physics & Astronomy, University of Waterloo, 200 University Avenue West, Waterloo, Ontario, Canada N2L 3G1.
authors.forename: D G
authors.initials: DG
authors.lastname: Hawthorn
authors.affiliation: Canadian Institute for Advanced Research, Canada, and Department of Physics & Astronomy, University of British Columbia, 6224 Agricultural Road, Vancouver, British Columbia, Canada V6T 1Z1.
authors.forename: G A
authors.initials: GA
authors.lastname: Sawatzky
authors.affiliation: Canadian Institute for Advanced Research, Canada, and Department of Physics & Astronomy, University of British Columbia, 6224 Agricultural Road, Vancouver, British Columbia, Canada V6T 1Z1.
authors.forename: R X
authors.initials: RX
authors.lastname: Liang
authors.affiliation: Canadian Institute for Advanced Research, Canada, and Department of Physics & Astronomy, University of British Columbia, 6224 Agricultural Road, Vancouver, British Columbia, Canada V6T 1Z1.
authors.forename: D A
authors.initials: DA
authors.lastname: Bonn
authors.affiliation: Canadian Institute for Advanced Research, Canada, and Department of Physics & Astronomy, University of British Columbia, 6224 Agricultural Road, Vancouver, British Columbia, Canada V6T 1Z1.
authors.forename: W N
authors.initials: WN
authors.lastname: Hardy
authors.affiliation: Department of Materials Science and Engineering, Brockhouse Institute and Canadian Centre for Electron Microscopy, McMaster University, 1280 Main Street West, Hamilton, Ontario, Canada L8S 4M1.
authors.forename: G A
authors.initials: GA
authors.lastname: Botton