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arXiv · 1005.0636

First-Principles Theory of Multipolar Order in Neptunium Dioxide

Michi-To Suzuki·Nicola Magnani·Peter M. Oppeneer
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Abstract

We provide a first-principle, materials-specific theory of multipolar order and superexchange in NpO$_2$ by means of a non-collinear local-density approximation +$U$ (LDA+$U$) method. Our calculations offer a precise microscopic description of the triple-$q$-antiferro ordered phase in the absence of any dipolar moment. We find that, while the most common non-dipolar degrees of freedom (e.g., electric quadrupoles and magnetic octupoles) are active in the ordered phase, both the usually neglected higher-order multipoles (electric hexadecapoles and magnetic triakontadipoles) have at least an equally significant effect.

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Michi-To Suzuki, Nicola Magnani, Peter M. Oppeneer. 2010-05-04. First-Principles Theory of Multipolar Order in Neptunium Dioxide. https://doi.org/10.1103/physrevb.82.241103

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