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Nonreciprocal Magnons and Symmetry-Breaking in the Noncentrosymmetric Antiffomagnet



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


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.
Physical Review Letters


nonreciiprocal magnon, noncentrosymmetric, neutron scattering


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], (Accessed June 16, 2024)


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Created July 23, 2017, Updated October 12, 2021