Eur. Phys. J. B 61, 405-411 (2008)
https://doi.org/10.1140/epjb/e2008-00108-y

Coulomb correlations do not fill the e^′_g hole pockets in Na_0.3CoO₂

¹ Institut für Festkörperforschung, Forschungszentrum Jülich, 52425 Jülich, Germany
² College of Humanities and Sciences, Nihon University, and CREST JST, Tokyo, 156, Japan

Received: 26 October 2007
Revised: 9 January 2008
Published online: 13 March 2008

Abstract

There exists presently considerable debate over the question whether local Coulomb interactions can explain the absence of the small e^′_g Fermi surface hole pockets in photoemission studies of Na_0.3CoO₂. By comparing dynamical mean field results for different single particle Hamiltonians and exact diagonalization as well as quantum Monte Carlo treatments, we show that, for realistic values of the Coulomb energy U and Hund exchange J, the e^′_g pockets can be slightly enhanced or reduced compared to band structure predictions, but they do not disappear.