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arXiv · 1102.0214

Low Temperature Dynamics of Magnons in a Spin-1/2 Ladder Compound

B. Náfrádi·T. Keller·H. Manaka·A. Zheludev·B. Keimer
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Abstract

We have used a combination of neutron resonant spin-echo and triple-axis spectroscopies to determine the energy, fine structure, and linewidth of the magnon resonance in the model spin-1/2 ladder antiferromagnet IPA-CuCl_3 at temperatures T << Delta_0 /k_B, where Delta_0 is the spin gap at T=0. In this low-temperature regime we find that the results deviate substantially from the predictions of the non-linear sigma model proposed as a description of magnon excitations in one-dimensional quantum magnets and attribute these deviations to real-space and spin-space anisotropies in the spin Hamiltonian as well as scattering of magnon excitations from a dilute density of impurities. These effects are generic to experimental realizations of one-dimensional quantum magnets.

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B. Náfrádi, T. Keller, H. Manaka, A. Zheludev, B. Keimer. 2011-02-01. Low Temperature Dynamics of Magnons in a Spin-1/2 Ladder Compound. https://doi.org/10.1103/physrevlett.106.177202

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