Physics – Condensed Matter – Strongly Correlated Electrons
Scientific paper
2006-06-20
PHYSICAL REVIEW B 74, 115124 (2006)
Physics
Condensed Matter
Strongly Correlated Electrons
10 pages, 4 figures
Scientific paper
10.1103/PhysRevB.74.115124
In order to shed light on the electronic structure of Na_xCoO_2, and motivated by recent Co L-edge X-ray absorption spectra (XAS) experiments with polarized light, we calculate the electronic spectrum of a CoO_6 cluster including all interactions between 3d orbitals. We obtain the ground state for two electronic occupations in the cluster that correspond nominally to all O in the O^{-2} oxidation state, and Co^{+3} or Co^{+4}. Then, all excited states obtained by promotion of a Co 2p electron to a 3d electron, and the corresponding matrix elements are calculated. A fit of the observed experimental spectra is good and points out a large Co-O covalency and cubic crystal field effects, that result in low spin Co 3d configurations. Our results indicate that the effective hopping between different Co atoms plays a major role in determining the symmetry of the ground state in the lattice. Remaining quantitative discrepancies with the XAS experiments are expected to come from composition effects of itineracy in the ground and excited states.
Aligia Armando A.
Kroll Th.
Sawatzky George. A.
No associations
LandOfFree
Polarization dependence of x-ray absorption spectra in Na_xCoO_2 does not yet have a rating. At this time, there are no reviews or comments for this scientific paper.
If you have personal experience with Polarization dependence of x-ray absorption spectra in Na_xCoO_2, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Polarization dependence of x-ray absorption spectra in Na_xCoO_2 will most certainly appreciate the feedback.
Profile ID: LFWR-SCP-O-621648