Phase Diagram of Na${}_x$CoO${}_2$ Studied by Gutzwiller Density Functional Theory

Abstract

The ground states of Na${}_x$CoO${}_2$ ($0.0<x<1.0$) is studied by the LDA+Gutzwiller approach, where charge transfer and orbital fluctuations are all self-consistently treated {\it ab-initio}. In contrast to previous studies, which are parameter-dependent, we characterized the phase diagram as: (1) Stoner magnetic metal for $x>0.6$ due to $a_{1g}$ van-Hove singularity near band top; (2) correlated non-magnetic metal without $e_g^{\prime }$ pockets for $0.3<x<0.6$; (3) $e_g^{\prime }$ pockets appear for $x<0.3$, and additional magnetic instability involves. Experimental quasi-particle properties is well explained, and the $a_{1g}$-$e_g^{\prime }$ anti-crossing is attributed to spin-orbital coupling.

4 pages, 3 figures

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Cited by in corpus (2)

• Correlation effects on the doped triangular lattice in view of the physics of sodium-rich Na${}_x$CoO${}_2$
• Dynamical mean field theory of an effective three-band model for Na${}_x$CoO${}_2$