title: Spectroscopy of stripe order in La1.8Sr0.2NiO4 using resonant soft x-ray diffraction.
abstract: Strong resonant enhancements of the charge-order and spin-order superstructure-diffraction intensities in La1.8Sr0.2NiO4 are observed when x-ray energies in the vicinity of the Ni L2,3 absorption edges are used. The pronounced photon-energy and polarization dependences of these diffraction intensities allow for a critical determination of the local symmetry of the ordered spin and charge carriers. We found that not only the antiferromagnetic order but also the charge-order superstructure resides within the NiO2 layers; the holes are mainly located on in-plane oxygens surrounding a Ni2+ site with the spins coupled antiparallel in close analogy to Zhang-Rice singlets in the cuprates.
authors.affiliation: II. Physikalisches Institut, Universität zu Köln, Zülpicher Strasse 77, D-50937 Köln, Germany.
authors.forename: C
authors.initials: C
authors.lastname: Schüssler-Langeheine
authors.forename: J
authors.initials: J
authors.lastname: Schlappa
authors.forename: A
authors.initials: A
authors.lastname: Tanaka
authors.forename: Z
authors.initials: Z
authors.lastname: Hu
authors.forename: C F
authors.initials: CF
authors.lastname: Chang
authors.forename: E
authors.initials: E
authors.lastname: Schierle
authors.forename: M
authors.initials: M
authors.lastname: Benomar
authors.forename: H
authors.initials: H
authors.lastname: Ott
authors.forename: E
authors.initials: E
authors.lastname: Weschke
authors.forename: G
authors.initials: G
authors.lastname: Kaindl
authors.forename: O
authors.initials: O
authors.lastname: Friedt
authors.forename: G A
authors.initials: GA
authors.lastname: Sawatzky
authors.forename: H-J
authors.initials: HJ
authors.lastname: Lin
authors.forename: C T
authors.initials: CT
authors.lastname: Chen
authors.forename: M
authors.initials: M
authors.lastname: Braden
authors.forename: L H
authors.initials: LH
authors.lastname: Tjeng