Theoretical spin-wave dispersions in the antiferromagnetic phase AF1 of MnWO₄ based on the polar atomistic model in P2

Abstract

The spin wave dispersions of the low temperature antiferromagnetic phase (AF1) MnWO have been numerically calculated based on the recently reported non-collinear spin configuration with two different canting angles. A Heisenberg model with competing magnetic exchange couplings and single-ion anisotropy terms could properly describe the spin wave excitations, including the newly observed low-lying energy excitation mode [Formula: see text] meV appearing at the magnetic zone centre. The spin wave dispersion and intensities are highly sensitive to two differently aligned spin-canting sublattices in the AF1 model. Thus this study reinsures the otherwise hardly provable hidden polar character in MnWO.