Hard x-ray spectroscopy in NaxCoO2 and superconducting NaxCoO2∙yH2O: Bulk Co electronic properties
Ph. Leininger, J.-P. Rueff, J.-M. Mariot, A. Yaresko, O. Proux, J.-L. Hazemann, G. Vankó, T. Sasaki, H. Ishii
DOI 10.1103/PhysRevB.74.075108 · Physical Review B
Active bibliographic source — not scientific approval
Bibliographic access preserves source history; it does not approve extracted materials or validate reported claims. Review warnings on each occurrence separately.
Abstract
The electronic properties of Co in bulk Na0.7CoO2 and the superconducting hydrated compound Na0.35CoO2∙yH2O have been investigated by x-ray absorption spectroscopy (XAS) and resonant inelastic x-ray scattering (RIXS) using hard x rays. The XAS spectra at the Co K-edge were measured in both compounds with two different polarization directions. The changes in the XAS spectra upon hydration and their polarization dependence are well accounted for by linear muffin-tin orbital calculations in the local density approximation. The underlying electronic structure indicates the strong hybridization between the Co 3d and O 2p states in both compounds, while the electron localization is enhanced in the hydrated compound due to the increase of the Co-Co interplanar distance. The Co K preedge further highlights the splitting of the d band as a result of the crystal field effect and demonstrates the Co valency increase when Na0.7CoO2 is hydrated. The RIXS spectra measured at the Co K edge show an energy loss feature around 10eV in both compounds, in fair agreement with the calculated dynamical structure factor. The RIXS feature is associated to a damped plasmon excitation.
Source-reported materials — not catalogue approval
| Formula | Reported Tc (K) | Pressure (GPa) | Type |
|---|---|---|---|
| Na0.35CoO2*yH2O Archive — visibility unverified Source-occurrence policy only; no material identity or catalogue acceptance is inferred from the formula. | 5 | Pressure not reported | unknown |
Similar papers
Observation of Bulk Superconductivity in NaxCoO2·yH2O and NaxCoO2·yD2O Powder and Single Crystals
similarity 0.94R. Jin et al.
Source status unknown — claims are unverified
Structure and dynamics of superconducting NaxCoO2 hydrate and its unhydrated analog
similarity 0.94J. W. Lynn et al.
Source status unknown — claims are unverified
Nuclear spin-lattice relaxation rate in the D1+iD2 superconducting state: Implications for CoO superconductor
similarity 0.94Yunkyu Bang et al.
Source status unknown — claims are unverified
Dynamics of water in the Na0.3CoO2∙1.4H2O superconductor
similarity 0.92V. García Sakai et al.
Source status unknown — claims are unverified
Influence of water intercalation on the electronic structure of the hydrated Na0.3CoO2.yH2O using a local spin density approximation
similarity 0.91R. J. Xiao et al. · 2006 · arXiv:cond-mat/0602629
Source status unknown — claims are unverified
Nesting, Spin Fluctuations, and Odd-Gap Superconductivity in NaxCoO2·yH2O
similarity 0.89M. D. Johannes et al.
Source status unknown — claims are unverified