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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
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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.

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T. Kroll, M. Knupfer, J. Geck, C. Hess, T. Schwieger, G. Krabbes, C. Sekar, D. R. Batchelor, H. Berger, B. Buechner. 2006-06-20. X-ray absorption spectroscopy on layered cobaltates Na_xCoO_2. https://doi.org/10.1103/physrevb.74.115123

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