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arXiv · 1007.2143

Spin Dynamics in $S=1/2$ Chains with Next-Nearest-Neighbor Exchange Interactions

M. Ozerov·A. A. Zvyagin·E. Čižmár·J. Wosnitza·R. Feyerherm·F. Xiao·C. P. Landee·S. A. Zvyagin
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Abstract

Low-energy magnetic excitations in the spin-1/2 chain compound (C$_6$H$_9$N$_2$)CuCl$_3$ [known as (6MAP)CuCl$_3$] are probed by means of tunable-frequency electron spin resonance. Two modes with asymmetric (with respect to the $h\nu=g\mu_B B$ line) frequency-field dependences are resolved, illuminating the striking incompatibility with a simple uniform $S=\frac{1}{2}$ Heisenberg chain model. The unusual ESR spectrum is explained in terms of the recently developed theory for spin-1/2 chains, suggesting the important role of next-nearest-neighbor interactions in this compound. Our conclusion is supported by model calculations for the magnetic susceptibility of (6MAP)CuCl$_3$, revealing a good qualitative agreement with experiment.

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M. Ozerov, A. A. Zvyagin, E. Čižmár, J. Wosnitza, R. Feyerherm, F. Xiao, C. P. Landee, S. A. Zvyagin. 2010-07-11. Spin Dynamics in $S=1/2$ Chains with Next-Nearest-Neighbor Exchange Interactions. https://doi.org/10.1103/physrevb.82.014416

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