Quasiparticle dispersion near the Fermi surface in NaxCoO2;

A. BOURGEOIS, A A ALIGIA, T. KROLL AND M. D. NÚÑEZ REGUEIRO

PHYSICA C - SUPERCONDUTIVITY

ELSEVIER SCIENCE BV

Año: 2007 vol. 460 p. 497 - 498

0921-4534

We construct an e.ective Hamiltonian for the motion of t2g highly correlated states in NaxCoO2 indirect Co?O?Co hopping t and the crystal-.field splitting 3D. Calculations in a CoO6 cluster give the effective parameters t = 100 meV and 3D = 315 meV. The Hamiltonian is solved using a generalized slave-boson mean-.eld approximation. The results show a signi.cant band renormalization. Without any additional hypothesis, the dispersion of the bands near the Fermi energy and Fermi surface topology agree with angle-resolved photoemission experiments, in contrast to predictions using the local-density approximation.