Neutron Scattering Study of Spin Chirality in YbMnBi2

This study investigates the mechanisms underlying the giant anomalous Nernst effect in the antiferromagnet YbMnBi2. Using polarized elastic neutron scattering, we uncovered hidden spin chirality with a transition temperature significantly above room temperature. Polarized inelastic neutron scattering revealed anisotropic spin fluctuations, and neutron single-crystal refinement demonstrated inversion symmetry breaking below the transition temperature of spin chirality. These findings suggest that Dzyaloshinskii-Moriya interactions likely drive the observed spin chirality, which in turn plays a crucial role in generating the large anomalous Nernst effect. Our results provide deeper insights into the contribution of spin chirality to anomalous transport phenomena such as anomalous Nernst effect.