Spin excitations in copper selenate, a skyrmion host material

Inelastic neutron scattering measurements performed at EIGER and TASP have mapped the magnetic excitation spectrum along high-symmetry directions of the first Brillouin zone for the magnetic skyrmion host copper selenate, Cu₂OSeO₃. Most of the observed spectrum is consistent with a recently proposed model for the magnetic excitations in Cu₂OSeO₃, for which a new set of best-fit dominant exchange parameters has been found. Two regions of the observed spectrum contain extra modes unexpected by the model which likely arise from neglected anisotropic interactions, suggesting that anisotropy should be considered in future efforts to fully understand the emergence of the skyrmion state in copper selenate.