Spin Hall effect emerging from a noncollinear magnetic lattice without spin-orbit coupling

The spin Hall effect (SHE), which converts a charge current into a transverse spin current, has long been believed to be a phenomenon induced by spin-orbit coupling. Here, we identify an alternative mechanism to realize the intrinsic SHE through a noncollinear magnetic structure that breaks the spin rotation symmetry. No spin-orbit coupling is needed even when the scalar spin chirality vanishes, different from the case of the topological Hall effect and topological SHE reported previously. In known noncollinear antiferromagnetic compounds Mn3X (X = Ga, Ge, and Sn), for example, we indeed obtain large spin Hall conductivities based on ab initio calculations.