Electronic structure and Fermi surface tolopogy of Na${}_x$CoO${}_2$

Abstract

We construct an effective Hamiltonian for the motion of T2g highly correlated states in NaxCoO2. We solve exactly a multiband model in a CoO6 cluster with electronic occupation corresponding to a nominal Co valence of either +3 or +4. Using the ensuing ground states, we calculate the effective O mediated hopping t=0.10 eV between many-body T2g states, and estimate the direct hopping t'~0.04 eV. The trigonal splitting 3D=0.315 eV is taken from recent quantum chemistry calculations. The resulting effective Hamiltonian is solved using a generalized slave-boson mean-field approximation. The results show a significant band renormalization and a Fermi surface topology that agrees with experiment, in contrast to predictions using the local-density approximation.

arXiv comment4 pages, 2 figures

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Cited by in corpus (12)

• Functional Renormalization Group for multi-orbital Fermi Surface Instabilities
• Anisotropic chiral d+id superconductivity in NaxCoO2 yH2O
• Elliptical hole pockets in the Fermi surfaces of unhydrated and hydrated sodium cobalt oxides
• Effective Hamiltonian for transition-metal compounds. Application to Na_xCoO_2
• Coulomb correlations do not fill the e'_g hole pockets in Na_{0.3}CoO_2
• Dynamical mean field theory of an effective three-band model for Na${}_x$CoO${}_2$
• Itinerant and localized magnetism on the triangular lattice: sodium rich phases of Na${}_x$CoO${}_2$
• The electronic structure of the Na${}_x$CoO${}_2$ surface
• Effect of covalency and interactions on the trigonal splitting in NaxCoO2
• Pressure effects in the triangular layered cobaltites NaxCoO2
• A possibility of high spin hole states in doped CoO${}_2$ layered systems
• Effect of Fermi-liquid interactions on the low-temperature de Haas - van Alphen oscillations in quasi-two-dimensional conductors