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arXiv · 1106.3665

Orbital order and magnetism of FeNCN

Alexander A. Tsirlin·Klaus Koepernik·Helge Rosner
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Abstract

Based on density functional calculations, we report on the orbital order and microscopic magnetic model of FeNCN, a prototype compound for orbital-only models. Despite having a similar energy scale, the spin and orbital degrees of freedom in FeNCN are only weakly coupled. The ground-state configuration features the doubly occupied d_{3z^2-r^2} (a1g) orbital and four singly-occupied d orbitals resulting in the spin S=2 on the Fe+2 atoms, whereas alternative (Eg') configurations are about 75 meV/f.u. higher in energy. Calculated exchange couplings and band gap are in good agreement with the available experimental data. Experimental effects arising from possible orbital excitations are discussed.

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Alexander A. Tsirlin, Klaus Koepernik, Helge Rosner. 2011-06-18. Orbital order and magnetism of FeNCN. https://arxiv.org/abs/1106.3665

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