Electronic theory for itinerant in-plane magnetic fluctuations in Na$_x$CoO$_2$

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dc.creatorKorshunov, M. M.
dc.creatorEremin, I.
dc.creatorShorikov, A.
dc.creatorAnisimov, V. I.
dc.date2006-08-15
dc.date2007-03-01
dc.date.accessioned2026-07-07T07:49:16Z
dc.date.available2026-07-07T07:49:16Z
dc.descriptionStarting from {\it ab-initio} band structure for Na$_x$CoO$_2$, we derive the single-electron energies and the effective tight-binding description for the $t_{2g}$ bands using a projection procedure. We find that 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. Therefore, in addition to a large Fermi surface an electron pocket close to the $Γ$ point emerges at high doping concentrations. The latter yields the new scattering channel resulting in a peak structure of the itinerant magnetic susceptibility at small momenta. This indicates itinerant in-plane ferromagnetic state above certain critical concentration $x_m$, in agreement with neutron scattering data. Below $x_m$ the magnetic susceptibility shows a tendency towards the antiferromagnetic fluctuations. We estimate the value of $0.58 < x_m < 0.7$ within the rigid band model and within the Hubbard model with infinite on-site Coulomb repulsion consistent with the experimental phase diagram.
dc.description4 pages, 4 figures; LDA calculations were done with Na in the symmetric 2d position contrary to the 6h position in a previous version of this paper
dc.identifierhttps://arxiv.org/abs/cond-mat/0608327
dc.identifierhttp://arxiv.org/abs/cond-mat/0608327
dc.identifierJETP Letters 84, 650 (2006) [Pis'ma v ZhETF 84, 769 (2006)]
dc.identifierdoi:10.1134/S0021364006240040
dc.identifier.urihttp://salesiana.dossiersoluciones.com/handle/123456789/124783
dc.subjectStrongly Correlated Electrons
dc.subjectSuperconductivity
dc.titleElectronic theory for itinerant in-plane magnetic fluctuations in Na$_x$CoO$_2$
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