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arXiv · 1607.08238

Field-induced decays in $XXZ$ triangular-lattice antiferromagnets

P. A. Maksimov·M. E. Zhitomirsky·A. L. Chernyshev
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Abstract

We investigate field-induced transformations in the dynamical response of the $XXZ$ model on the triangular lattice that are associated with the anharmonic magnon coupling and decay phenomena. A set of concrete theoretical predictions is made for a close physical realization of the spin-1/2 $XXZ$ model, Ba$_3$CoSb$_2$O$_9$. We demonstrate that dramatic modifications in magnon spectrum must occur in low out-of-plane fields that are easily achievable for this material. The hallmark of the effect is a coexistence of the clearly distinct well-defined magnon excitations with significantly broadened ones in different regions of the ${\bf k}-ω$ space. The field-induced decays are generic for this class of models and become more prominent at larger anisotropies and in higher fields.

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P. A. Maksimov, M. E. Zhitomirsky, A. L. Chernyshev. 2016-09-21. Field-induced decays in $XXZ$ triangular-lattice antiferromagnets. https://doi.org/10.1103/physrevb.94.140407

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