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

Liang-Jian Zou·J. -L. Wang·Z. Zeng
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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$_{pdσ}$ and t$_{pdπ}$ 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.

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Liang-Jian Zou, J. -L. Wang, Z. Zeng. 2003-07-24. Electronic States in Two-Dimensional Triangular Cobalt Oxides: Role of Electronic Correlation. https://doi.org/10.1103/physrevb.69.132505

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