Dynamical Mean Field Theory of an Effective Three-Band Model for NaxCoO2

A. BOURGEOIS, A. A. ALIGIA, AND M. J. ROZENBERG

PHYSICAL REVIEW LETTERS

AMER PHYSICAL SOC

Lugar: New York; Año: 2009 vol. 102 p. 664021 - 664024

0031-9007

   We derive an effective Hamiltonian for highly correlated t2g states centered at the Co sites of Nax CoO2 .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.