Spectroscopy of stripe order in La1.8Sr0.2NiO4 using resonant soft x-ray diffraction.
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.
Schüssler-Langeheine
C
C
II. Physikalisches Institut, Universität zu Köln, Zülpicher Strasse 77, D-50937 Köln, Germany.
Schlappa
J
J
Tanaka
A
A
Hu
Z
Z
Chang
C F
CF
Schierle
E
E
Benomar
M
M
Ott
H
H
Weschke
E
E
Kaindl
G
G
Friedt
O
O
Sawatzky
G A
GA
Lin
H-J
HJ
Chen
C T
CT
Braden
M
M
Tjeng
L H
LH