Role of electronic correlations in the Fermi surface formation of NaxCoO2
A. Shorikov, M. M. Korshunov*,∇, V. I. Anisimov
Institute of Metal Physics Ural Division RAS, 620219 Yekaterinburg GSP-170, Russia
*L.V. Kirensky Institute of Physics, Siberian Branch of RAS, 660036 Krasnoyarsk, Russia
∇Max-Planck-Institut für Physik komplexer Systeme, D-01187 Dresden, Germany
Abstract
Band structure of metallic sodium cobaltate NaxCO2
(x=0.33, 0.48, 0.61 0.72) has been investigated by local density
approximation+Hubbard U (LDA+U) method and within Gutzwiller
approximation for the Co-t2g manifold. Correlation effects being taken
into account results in suppression of the e'g hole pockets at the Fermi
surface in agreement with recent angle-resolved photo-emission spectroscopy
(ARPES) experiments. In the Gutzwiller approximation the bilayer splitting is
significantly reduced due to the correlation effects. The formation of high
spin (HS) state in Co d-shell was shown to be very improbable.