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.

4 pages, 2 figures

References in corpus (8)

• Fermi surface and quasiparticle dynamics of Na(x)CoO2 {x=0.7} investigated by Angle-Resolved Photoemission Spectroscopy
• Fermi surface evolution and Luttinger theorem in Na${}_x$CoO${}_2$: a systematic photoemission study
• ARPES on Na${}_{0.6}$CoO${}_2$: Fermi surface, extended flat dispersion, and unusual band splitting
• Electron correlation and Fermi surface topology of Na${}_x$CoO${}_2$
• An ab-initio evaluation of the local effective interactions in the superconducting compound $Na\_0.35CoO\_2-1.3H\_2O$
• Destruction of the small Fermi surfaces in Na${}_x$CoO${}_2$ by Na disorder
• X-ray absorption spectroscopy on layered cobaltates Na_xCoO_2
• Polarization dependence of x-ray absorption spectra in Na_xCoO_2

Cited by in corpus (7)

• Elliptical hole pockets in the Fermi surfaces of unhydrated and hydrated sodium cobalt oxides
• Dynamical mean field theory of an effective three-band model for Na${}_x$CoO${}_2$
• Coulomb correlations do not fill the e'_g hole pockets in Na_{0.3}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
• Pressure effects in the triangular layered cobaltites NaxCoO2
• Effect of Fermi-liquid interactions on the low-temperature de Haas - van Alphen oscillations in quasi-two-dimensional conductors