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 . 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.
, Zhao, Y.
, Piyawongwatthana, P.
, Qiu, Y.
, Harriger, L.
, Butch, N.
, Sato, T.
and Matan, K.
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 3, 2023)