title: Orbital Reconstruction in a Self-assembled Oxygen Vacancy Nanostructure.
abstract: We demonstrate the microscopic role of oxygen vacancies spatially confined within nanometer inter-spacing (about 1 nm) in BiFeO3, using resonant soft X-ray scattering techniques and soft X-ray spectroscopy measurements. Such vacancy confinements and total number of vacancy are controlled by substitution of Ca(2+) for Bi(3+) cation. We found that by increasing the substitution, the in-plane orbital bands of Fe(3+) cations are reconstructed without any redox reaction. It leads to a reduction of the hopping between Fe atoms, forming a localized valence band, in particular Fe 3d-electronic structure, around the Fermi level. This band localization causes to decrease the conductivity of the doped BiFeO3 system.
authors.affiliation: Stanford Synchrotron Radiation Lightsource, SLAC National Accelerator Laboratory, Menlo Park, California 94025, USA.
authors.forename: H
authors.initials: H
authors.lastname: Jang
authors.affiliation: Stanford Synchrotron Radiation Lightsource, SLAC National Accelerator Laboratory, Menlo Park, California 94025, USA.
authors.forename: G
authors.initials: G
authors.lastname: Kerr
authors.affiliation: Department of Physics, KAIST, Yuseong-gu, Daejeon 305-701, South Korea.
authors.forename: J S
authors.initials: JS
authors.lastname: Lim
authors.affiliation: Department of Physics, KAIST, Yuseong-gu, Daejeon 305-701, South Korea.
authors.forename: C-H
authors.initials: CH
authors.lastname: Yang
authors.affiliation: SLAC National Accelerator Laboratory, Menlo Park, California 94025, USA.
authors.forename: C-C
authors.initials: CC
authors.lastname: Kao
authors.affiliation: Stanford Synchrotron Radiation Lightsource, SLAC National Accelerator Laboratory, Menlo Park, California 94025, USA.
authors.forename: J-S
authors.initials: JS
authors.lastname: Lee