Itinerant in-plane magnetic fluctuations and many-body correlations in Nax Co O2

M. M. Korshunov, I. Eremin, A. Shorikov, V. I. Anisimov, M. Renner, W. Brenig

Research output: Contribution to journalArticlepeer-review

30 Citations (Scopus)

Abstract

Based on the ab initio band structure for Nax Co O2, we derive the single-electron energies and the effective tight-binding description for the t2g bands using projection procedure. Due to the presence of the next-nearest-neighbor hoppings, a local minimum in the electronic dispersion close to the Γ point of the first Brillouin zone forms. Correspondingly, in addition to a large Fermi surface, an electron pocket close to the Γ point emerges at high doping concentrations. The latter yields a scattering channel, resulting in a peak structure of the itinerant magnetic susceptibility at small momenta. This indicates dominant itinerant in-plane ferromagnetic fluctuations above a certain critical concentration xm, in agreement with neutron scattering data. Below xm, the magnetic susceptibility shows a tendency toward the antiferromagnetic fluctuations. We further analyze the many-body effects on the electronic and magnetic excitations using various approximations applicable for different Ut ratios.

Original languageEnglish
Article number094511
JournalPhysical Review B - Condensed Matter and Materials Physics
Volume75
Issue number9
DOIs
Publication statusPublished - 28 Mar 2007
Externally publishedYes

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