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arXiv · 2006.13538

Nature of Magnetic Excitations in the High-Field Phase of $\alpha$-RuCl$_3$

A. N. Ponomaryov·L. Zviagina·J. Wosnitza·P. Lampen-Kelley·A. Banerjee·J. -Q. Yan·C. A. Bridges·D. G. Mandrus·S. E. Nagler·S. A. Zvyagin
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Abstract

We present comprehensive electron spin resonance (ESR) studies of in-plane oriented single crystals of $\alpha$-RuCl$_3$, a quasi-two-dimensional material with honeycomb structure, focusing on its high-field spin dynamics. The measurements were performed in magnetic fields up to 16 T, applied along the [110] and [100] directions. Several ESR modes were detected. Combining our findings with recent inelastic neutron- and Raman-scattering data, we identify most of the observed excitations. Most importantly, we show that the low-temperature ESR response beyond the boundary of the magnetically ordered region is dominated by single- and two-particle processes with magnons as elementary excitations. The peculiarities of the excitation spectrum in the vicinity of the critical field are discussed.

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A. N. Ponomaryov, L. Zviagina, J. Wosnitza, P. Lampen-Kelley, A. Banerjee, J. -Q. Yan, C. A. Bridges, D. G. Mandrus, S. E. Nagler, S. A. Zvyagin. 2020-06-24. Nature of Magnetic Excitations in the High-Field Phase of $\alpha$-RuCl$_3$. https://doi.org/10.1103/physrevlett.125.037202

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