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arXiv · 1306.3887

Magnetic excitations in the spin-1/2 triangular-lattice antiferromagnet Cs$_2$CuBr$_4$

S. A. Zvyagin·M. Ozerov·D. Kamenskyi·J. Wosnitza·J. Krzystek·D. Yoshizawa·M. Hagiwara·Rongwei Hu·Hyejin Ryu·C. Petrovic·M. E. Zhitomirsky
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Abstract

We report on high-field electron spin resonance (ESR) studies of magnetic excitations in the spin-1/2 triangular-lattice antiferromagnet Cs$_2$CuBr$_4$. Frequency-field diagrams of ESR excitations are measured for different orientations of magnetic fields up to 25 T. We show that the substantial zero-field energy gap, $\Delta\approx9.5$ K, observed in the low-temperature excitation spectrum of Cs$_2$CuBr$_4$ [Zvyagin $et~al.$, Phys. Rev. Lett. 112, 077206 (2014)], is present well above $T_N$. Noticeably, the transition into the long-range magnetically ordered phase does not significantly affect the size of the gap, suggesting that even below $T_N$ the high-energy spin dynamics in Cs$_2$CuBr$_4$ is determined by short-range-order spin correlations. The experimental data are compared with results of model spin-wave-theory calculations for spin-1/2 triangle-lattice antiferromagnet.

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S. A. Zvyagin, M. Ozerov, D. Kamenskyi, J. Wosnitza, J. Krzystek, D. Yoshizawa, M. Hagiwara, Rongwei Hu, Hyejin Ryu, C. Petrovic, M. E. Zhitomirsky. 2013-06-17. Magnetic excitations in the spin-1/2 triangular-lattice antiferromagnet Cs$_2$CuBr$_4$. https://doi.org/10.1088/1367-2630/17/11/113059

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