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arXiv · 0706.3413

Orbital ordering in the ferromagnetic insulator Cs$_2$AgF$_4$ from first principles

Hua Wu·D. I. Khomskii
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Abstract

We found, using density-functional theory calculations within the generalized gradient approximation, that Cs$_2$AgF$_4$ is stabilized in the insulating orthorhombic phase rather than in the metallic tetragonal phase. The lattice distortion present in the orthorhombic phase corresponds to the $x^2-z^2$/$y^2-z^2$ hole-orbital ordering of the Ag$^{2+}$ $4d^9$ ions, and this orbital ordering leads to the observed ferromagnetism, as confirmed by the present total-energy calculations. This picture holds in the presence of moderate 4d-electron correlation. The results are compared with the picture of ferromagnetism based on the metallic tetragonal phase.

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Hua Wu, D. I. Khomskii. 2007-08-28. Orbital ordering in the ferromagnetic insulator Cs$_2$AgF$_4$ from first principles. https://doi.org/10.1103/physrevb.76.155115

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