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Zeeman levels with exotic field dependence in the high field phase of a S=1 Heisenberg antiferromagnetic chain

M. Hagiwara·Z. Honda·K. Katsumata·A. K. Kolezhuk·H. -J. Mikeska
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Abstract

We have performed electron spin resonance measurements over a wide frequency and magnetic field range on a single crystal of the S=1 quasi-one-dimensional Heisenberg antiferromagnet $\rm Ni(C_5H_{14}N_2)_2N_3(PF_6)$. We observed gapped excitation branches above the critical field ($H_{\rm c}$) where the Haldane gap closes. These branches are analyzed by a phenomenological field-theory using complex-field $ϕ^{4}$ model. A satisfactory agreement between experiment and theory is obtained.

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M. Hagiwara, Z. Honda, K. Katsumata, A. K. Kolezhuk, H. -J. Mikeska. 2003-06-20. Zeeman levels with exotic field dependence in the high field phase of a S=1 Heisenberg antiferromagnetic chain. https://doi.org/10.1103/physrevlett.91.177601

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