Non-reciprocal magnons in non-centrosymmetric MnSi

TL;DR

This study maps the non-reciprocal magnon dispersion relations in MnSi across all magnetic phases, revealing asymmetries in the dynamical structure factor related to magnetic field, momentum, and energy transfer.

Contribution

It provides the first comprehensive experimental mapping of field-dependent non-reciprocal magnons in MnSi using neutron spectroscopy.

Findings

Demonstrates full asymmetry in the dynamical structure factor

Reveals non-reciprocal magnon behavior in all magnetic phases

Shows dependence of non-reciprocity on magnetic field, momentum, and energy

Abstract

Using two cold-neutron triple-axis spectrometers we have succeeded in fully mapping out the field-dependent evolution of the non-reciprocal magnon dispersion relations in all magnetic phases of MnSi. The non-reciprocal nature of the dispersion manifests itself in a full asymmetry (non-reciprocity) of the dynamical structure factor $S(q, E, \mu_0 H_{int})$ with respect to flipping either the direction of the applied magnetic field $\mu_0 H_{int}$, the reduced momentum transfer $q$, or the energy transfer $E$.