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Pis'ma v Zhurnal Èksperimental'noi i Teoreticheskoi Fiziki, 2006, Volume 84, Issue 12, Pages 769–774
(Mi jetpl1210)
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This article is cited in 10 scientific papers (total in 10 papers)
CONDENSED MATTER
Electronic theory for itinerant in-plane magnetic fluctuations in $\mathrm{Na_xCoO_2}$
M. M. Korshunovab, I. M. Ereminac, A. O. Shorikovd, V. I. Anisimovd a L. V. Kirensky Institute of Physics, Siberian Branch of the Russian Academy of Sciences
b Max-Planck-Institut für Physik komplexer Systeme, D-01187 Dresden, Germany
c Institut für Mathematische Physik and Theoretische Physik, TU Braunschweig, 38106 Braunschweig, Germany
d Institute of Metal Physics, RAS-Ural Division
Abstract:
Starting from ab-initio band structure for $\mathrm{Na_xCoO_2}$, 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 $\Gamma$ point of the first Brillouin zone forms. Therefore, in addition to a large Fermi surface an electron pocket close to the $\Gamma$ 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 $0.56<x_m<0.68$ within the rigid band model and within the Hubbard model with infinite on-site Coulomb repulsion consistent with the experimental phase diagram.
Received: 30.10.2006
Citation:
M. M. Korshunov, I. M. Eremin, A. O. Shorikov, V. I. Anisimov, “Electronic theory for itinerant in-plane magnetic fluctuations in $\mathrm{Na_xCoO_2}$”, Pis'ma v Zh. Èksper. Teoret. Fiz., 84:12 (2006), 769–774; JETP Letters, 84:12 (2006), 650–655
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https://www.mathnet.ru/eng/jetpl1210 https://www.mathnet.ru/eng/jetpl/v84/i12/p769
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