Electronic States in Two-Dimensional Triangular Cobalt Oxides: Role of Electronic Correlation

Abstract

We obtain the electronic states and structures of two-dimensional cobalt oxides, Na${}_x$CoO${}_2$ (x=0, 0.35, 0.5 and 0.75) by utilizing the full-potential linear muffin-tin orbitals (FP-LMTO) methods, from which some essential electronic interaction parameters are estimated: the bare on-site Coulomb interaction of cobalt U${}_{dd}$=7.5 eV renormalizes to 5 eV for x=0.35, the $pd$ hybridizations t${}_{pd\sigma }$ and t${}_{pd\pi }$ are -1.40 and 0.70 eV, respectively. The density of states at E${}_F$ decreases from 6-7 states/eV in the local density approximation (LDA) to about 1.0 states/eV in the LDA+U scheme. The role of the intercalation of water molecules and the microscopic mechanism of the superconductivity in Na${}_{0.35}$CoO${}_2$$\cdot$mH${}_2$O is discussed.

minor errors corrected

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Cited by in corpus (20)

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• The Fermi surface of Na${}_x$CoO${}_2$
• Effect of Dynamical Coulomb Correlations on the Fermi Surface of Na_0.3CoO_2
• Magnetic susceptibility study of hydrated and non-hydrated NaxCoO2-yH2O single crystals
• Disproportionation Transition at Critical Interaction Strength: Na${}_{1/2}$CoO${}_2$
• Na content dependence of superconductivity and the spin correlations in Na_{x}CoO_{2}\cdot 1.3H_{2}O
• An ab-initio evaluation of the local effective interactions in the superconducting compound $Na\_0.35CoO\_2-1.3H\_2O$
• Geometrical, electronic and magnetic properties of Na${}_{0.5}$CoO${}_2$ from first principles
• Orbitally relieved magnetic frustration in NaVO2
• Na${}_x$CoO${}_2$ in the x -> 0 Regime: Coupling of Structure and Correlation effects
• Theoretical analysis of oxygen vacancies in layered sodium cobaltate Na_xCoO_{2-δ}
• Optical Study of the Electronic Structure and Correlation Effects in K0.49RhO2
• Electronic Structure of Sodium Cobalt Oxide: Comparing Mono- and Bilayer-hydrate
• Role of electronic correlations in the Fermi surface formation of Na${}_x$CoO${}_2$
• Hard x-ray spectroscopy in NaxCoO2 and superconducting NaxCoO2 - yH2O: A view on the bulk Co electronic properties
• A possibility of high spin hole states in doped CoO${}_2$ layered systems
• Evolution of electron Fermi surface with doping in cobaltates