Dynamical mean field theory of an effective three-band model for NaxCoO2.
We derive an effective Hamiltonian for highly correlated t_{2g} states centered at the Co sites of NaxCoO2. The essential ingredients of the model are an O mediated hopping, a trigonal crystal-field splitting, and on-site effective interactions derived from the exact solution of a multiorbital model in a CoO6 cluster, with parameters determined previously. The effective model is solved by dynamical mean field theory. We obtain a Fermi surface and electronic dispersion that agrees well with angle-resolved photoemission spectra. Our results also elucidate the origin of the "sinking pockets" in different doping regimes.
Bourgeois
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Laboratoire de Physique des Solides, Université Paris-Sud, CNRS UMR-8502, 91405 Orsay cedex, France.
Aligia
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Rozenberg
M J
MJ