Nonreciprocal Magnons and Symmetry-Breaking in the Noncentrosymmetric Antiffomagnet

Published

July 24, 2017

Author(s)

G. Gitgeatpong, Yang Zhao, P. Piyawongwatthana, Yiming Qiu, Leland Harriger, Nicholas Butch, T. J. Sato, K. Matan

Abstract

Magnons, the spin-wave quanta, are disturbances that embody a wave propagating through a back-ground medium formed by ordered magnetic moments. In an isotropic Heisenberg system, these disturbances vary in a continuous manner around an ordered spin structure, thus requiring infinitesimal energy as a wavevector approaches a magnetic zone centre. However, competing anisotropic interactions arising from broken symmetry can favour distinct static and dynamic spin state causing a shift of the minimum point of the magnon dispersion to a nonreciprocal wavevector [1]. Here we report the first direct evidence of the nonreciprocal magnons in the noncentrosymmetric antiferromagnet α-Cu₂V₂O₇. In this system, the incompatibility between anisotropic exchange and antisymmetric Dzyaloshinskii-Moriya interactions results in competing collinear and helical spin structures. The breaking of spatial inversion and time reversal symmetry is revealed as a field-induced asymmetric energy shift, which provides a test for the detailed balance relation.

Citation

Physical Review Letters

Volume

119

Issue

4

Pub Type

Journals

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Keywords

nonreciiprocal magnon, noncentrosymmetric, neutron scattering

Citation

Gitgeatpong, G. , Zhao, Y. , Piyawongwatthana, P. , Qiu, Y. , Harriger, L. , Butch, N. , Sato, T. and Matan, K. (2017), Nonreciprocal Magnons and Symmetry-Breaking in the Noncentrosymmetric Antiffomagnet, Physical Review Letters, [online], https://tsapps.nist.gov/publication/get_pdf.cfm?pub_id=922841 (Accessed December 14, 2024)