Polarized inelastic neutron scattering of nonreciprocal spin waves in MnSi

Systems lacking time-inversion or centrosymmetry exhibit nonreciprocal magnon transport. Their dynamical magnetic structure factor is asymmetric with respect to the inversion of the reduced momentum, transferred to the system. In this work, the authors establish the helical itinerant-electron magnet MnSi as an archetypical model for nonreciprocal phenomena by comparing polarized inelastic neutron scattering data with mean-field linear spin-wave calculations.