Field Induced Spontaneous Quasiparticle Decay and Renormalization of Quasiparticle Dispersion in a Quantum Antiferromagnet

Published

May 5, 2017

Author(s)

Tao Hong, Yiming Qiu, M. Matsumoto, D. A. Tennant, K. Coester, K. P. Schmidt, F.F. Awwadi, M. M. Turnbull, H. Agrawal, A. L. Chernyshev

Abstract

We present the fine-resolution neutron scattering study in magnetic fields applied perpendicular to an easy-axis (Ising type) on the S=1/2 coupled two-leg ladder antiferromagnet (dimethylammonium)(3,5-dimethylpyridinium)CuBr₄. At finite fields, the magnetic structure becomes non-collinearly canted and the observed intriguing renormalization of one-magnon dispersion near the Brillouin Zone center and spontaneous magnon decays over a large region of the Brillouin Zone in the excitation spectra can be well explained by the mechanism where the process of one-magnon decays into the two-magnon continuum is kinematically allowed. We also find that field dependence of the Zeeman energy Δ} behaves in the same way as the temperature dependence of a spin gap in quasi-one-dimensional quantum disordered magnets. A universal scaling calculated by the O(3) non-linear sigma model for finite temperature effects with an overall prefactor is surprisingly valid over at least up to gυBH/δH=O approximately equal}1.8.

Citation

Nature Communications

Volume

8

Issue

15148

Pub Type

Journals

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Keywords

neutron scattering, spontaneous magnon decay, universal scaling

Citation

Hong, T. , Qiu, Y. , Matsumoto, M. , Tennant, D. , Coester, K. , Schmidt, K. , Awwadi, F. , Turnbull, M. , Agrawal, H. and Chernyshev, A. (2017), Field Induced Spontaneous Quasiparticle Decay and Renormalization of Quasiparticle Dispersion in a Quantum Antiferromagnet, Nature Communications, [online], https://tsapps.nist.gov/publication/get_pdf.cfm?pub_id=920051 (Accessed November 6, 2025)