Electronic structure and Fermi surface tolopogy of Na$_x$CoO$_2$
Abstract
We construct an effective Hamiltonian for the motion of T2g highly correlated states in NaxCoO2. We solve exactly a multiband model in a CoO6 cluster with electronic occupation corresponding to a nominal Co valence of either +3 or +4. Using the ensuing ground states, we calculate the effective O mediated hopping t=0.10 eV between many-body T2g states, and estimate the direct hopping t'~0.04 eV. The trigonal splitting 3D=0.315 eV is taken from recent quantum chemistry calculations. The resulting effective Hamiltonian is solved using a generalized slave-boson mean-field approximation. The results show a significant band renormalization and a Fermi surface topology that agrees with experiment, in contrast to predictions using the local-density approximation.
Keywords
Cite
@article{arxiv.cond-mat/0610173,
title = {Electronic structure and Fermi surface tolopogy of Na$_x$CoO$_2$},
author = {A. Bourgeois and A. A. Aligia and T. Kroll and M. D. Núñez-Regueiro},
journal= {arXiv preprint arXiv:cond-mat/0610173},
year = {2009}
}
Comments
4 pages, 2 figures