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arXiv · 0801.0598

Quantum order by disorder in frustrated diamond lattice antiferromagnets

Jean-Sebastien Bernier·Michael J. Lawler·Yong Baek Kim
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Abstract

We present a quantum theory of frustrated diamond lattice antiferromagnets. Considering quantum fluctuations as the predominant mechanism relieving spin frustration, we find a rich phase diagram comprising of six phases with coplanar spiral ordering in addition to the Néel phase. By computing the specific heat of these ordered phases, we obtain a remarkable agreement between $(k,k,0)$-spiral ordering and the experimental specific heat data for the diamond lattice spinel compounds MnSc$_2$S$_4$, Co$_3$O$_4$ and CoRh$_2$O$_4$, i.e. specific heat data is a strong evidence for $(k,k,0)$-spiral ordering in all of these materials. This prediction can be tested in future neutron scattering experiments on Co$_3$O$_4$ and CoRh$_2$O$_4$, and is consistent with existing neutron scattering data on MnSc$_2$S$_4$. Based on this agreement we infer a monotonically increasing relationship between frustration and the strength of quantum fluctuations.

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Jean-Sebastien Bernier, Michael J. Lawler, Yong Baek Kim. 2008-09-10. Quantum order by disorder in frustrated diamond lattice antiferromagnets. https://doi.org/10.1103/physrevlett.101.047201

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