X-ray absorption spectroscopy on layered cobaltates Na_xCoO_2

T. Kroll; M. Knupfer; J. Geck; C. Hess; T. Schwieger; G. Krabbes; C. Sekar; D. R. Batchelor; H. Berger; B. Buechner

doi:10.1103/PhysRevB.74.115123

X-ray absorption spectroscopy on layered cobaltates Na_xCoO_2

Strongly Correlated Electrons 2009-11-11 v1

Authors: T. Kroll , M. Knupfer , J. Geck , C. Hess , T. Schwieger , G. Krabbes , C. Sekar , D. R. Batchelor , H. Berger , B. Buechner

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Abstract

Measurements of polarization and temperature dependent soft x-ray absorption have been performed on Na_xCoO_2 single crystals with x=0.4 and x=0.6. They show a deviation of the local trigonal symmetry of the CoO_6 octahedra, which is temperature independent in a temperature range between 25 K and 372 K. This deviation was found to be different for Co^{3+} and Co^{4+} sites. With the help of a cluster calculation we are able to interpret the Co L_{23}-edge absorption spectrum and find a doping dependent energy splitting between the t_{2g} and the e_g levels (10Dq) in Na_xCoO_2.

Keywords

X-ray absorption spectroscopy layered cobaltates Na_xCoO_2 crystal field splitting cluster calculation local symmetry

Cite

@article{arxiv.cond-mat/0606518,
  title  = {X-ray absorption spectroscopy on layered cobaltates Na_xCoO_2},
  author = {T. Kroll and M. Knupfer and J. Geck and C. Hess and T. Schwieger and G. Krabbes and C. Sekar and D. R. Batchelor and H. Berger and B. Buechner},
  journal= {arXiv preprint arXiv:cond-mat/0606518},
  year   = {2009}
}

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7 pages, 8 figures

X-ray absorption spectroscopy on layered cobaltates Na_xCoO_2

Abstract

Keywords

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