Two spin-canting textures in the antiferromagnetic phase AF1 of MnWO₄ based on the new polar atomistic model in P2

The low temperature antiferromagnetic (AF) phase of MnWO₄ (the so-called AF1 phase) exhibits different spin-canting configurations at two Mn²⁺ sublattices of the (3  +  1)-dimensional magnetic structure. The suggested superspace group [Formula: see text] is a significant consequence of the polar space group [Formula: see text]2 true for the nuclear structure of MnWO₄. Density functional theory calculations showed that its ground state prefers this two spin-canting system. The structural difference between two independent atomic sites for Mn (Mn _a , Mn _b ) is too small to allow microscopically detectable electric polarisation. However, this hidden intrinsic polar character allows AF1 two commensurately modulated spin-canting textures. This is considered as the prerequisite onset of the improper ferroelectricity enhanced by the helical spin order in the multiferroic phase AF2 of MnWO₄.