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arXiv · 0709.2520

Orbital-quenching-induced magnetism in Ba_2NaOsO_6

K. -W. Lee·W. E. Pickett
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Abstract

The double perovskite \bnoo with heptavalent Os ($d^1$) is observed to remain in the ideal cubic structure ({\it i.e.} without orbital ordering) despite single occupation of the $t_{2g}$ orbitals, even in the ferromagnetically ordered phase below 6.8 K. Analysis based on the {\it ab initio} dispersion expressed in terms of an Os $t_{2g}$-based Wannier function picture, spin-orbit coupling, Hund's coupling, and strong Coulomb repulsion shows that the magnetic OsO$_6$ cluster is near a moment-less condition due to spin and orbital compensation. Quenching (hybridization) then drives the emergence of the small moment. This compensation, unprecedented in transition metals, arises in a unified picture that accounts for the observed Mott insulating behavior.

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K. -W. Lee, W. E. Pickett. 2007-09-16. Orbital-quenching-induced magnetism in Ba_2NaOsO_6. https://doi.org/10.1209/0295-5075/80/37008

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