Optical Properties and Correlation Effects in Na_xCoO₂

Journal Article · Sat Jan 01 04:00:00 EST 2005 · Physical Review B

DOI:https://doi.org/10.1103/PhysRevB.71.205103· OSTI ID:1003087

Johannes, M. D. ^[1]; Mazin, I. I. ^[1]; Singh, David J ^[2]

---

1. Naval Research Laboratory, Washington, D.C.
2. ORNL

We have calculated the optical spectra of Na{sub x}CoO{sub 2} for x=0.3, 0.5, and 0.7 within the local density approximation (LDA). A comparison of our results to available experimental data shows good agreement of the important features and trends, but reveals a nearly uniform shift of peak positions and poor quantitative reproduction of intensities. We show, through application of a simple model, that these differences can be attributed to overhybridization between Co and O orbitals and spin fluctuations that renormalize the bandwidth. Application of the LDA+U procedure shifts the optical peaks farther from their experimental locations, indicating that this method of incorporating correlation effects is ill-suited for the case of Na{sub x}CoO{sub 2}.

• Research Organization: Oak Ridge National Laboratory (ORNL)
• Sponsoring Organization: SC USDOE - Office of Science (SC)
• DOE Contract Number: AC05-00OR22725
• OSTI ID: 1003087
• Journal Information: Physical Review B, Journal Name: Physical Review B Journal Issue: 20 Vol. 71; ISSN 1098-0121; ISSN 1550-235X
• Country of Publication: United States
• Language: English

Related Subjects

37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CHEMISTRY
COBALT OXIDES
CORRELATIONS
ELECTRONIC STRUCTURE
MATHEMATICAL MODELS
OPTICAL PROPERTIES
SODIUM OXIDES
SPECTRA
SPIN