Effect of Dynamical Coulomb Correlations on the Fermi Surface ofNa0.3CoO2

The $t_{2g}$ quasiparticle spectra of ${\mathrm{Na}}_{0.3}{\mathrm{CoO}}_2$ are calculated within the dynamical mean field theory. It is shown that as a result of dynamical Coulomb correlations charge is transferred from the nearly filled $e_{g^{\prime }}$ subbands to the $a_{1g}$ band, thereby reducing orbital polarization among Co $t_{2g}$ states. Dynamical correlations therefore stabilize the small $e_{g^{\prime }}$ Fermi surface pockets, in contrast to angle-resolved photoemission data, which do not reveal these pockets.