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arXiv · 1204.3101

Ab-initio studying of spin states of sodium cobaltate Na$_{2/3}$CoO$_2$

Y. Lysogorskiy·O. Nedopekin·S. Krivenko·D. Tayurskii·B. Minisini
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Abstract

Puzzling properties of sodium cobaltates Na${}_x$CoO${}_2$ become an issue of numerous recent theoretical and experimental investigations because of very high thermopower and intricate phase diagram of this material. Experiments indicated Na${}_{2/3}$CoO${}_2$ to have a kagome-like cobalt sublattice, which implies additional complexity of this strongly correlated system. In the present work we have employed the ab-initio GGA+U modeling method to investigate spin states of Na${}_{2/3}$CoO${}_2$, using an exact crystal cell established in the experiment. Stability of sodium imprint for concentration $x=2/3$ proposed in the publications has been obtained. An AFM-A type magnetic ordering has been recognized as a ground state. Moreover, a competition between low spin state (LS) and intermediate spin state (IS) has been established to depend on on-site Hubbard $U$ correction parameter. LS state has been identified as a ground state of Na${}_{2/3}$CoO${}_2$.

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Y. Lysogorskiy, O. Nedopekin, S. Krivenko, D. Tayurskii, B. Minisini. 2012-04-13. Ab-initio studying of spin states of sodium cobaltate Na$_{2/3}$CoO$_2$. https://doi.org/10.1088/1742-6596/394/1/012019

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