Numerical evidence for spin chirality emerging from itinerant ferromagnets in bands with Berry curvature

Abstract

The behavior of strongly interacting electrons in bands with Berry curvature is a problem of wide interest. In this paper, we study this problem by numerically studying a fluxed Hubbard-type model on square lattice. Using this model, we demonstrate a metallic ferromagnet in electron bands equipped with Berry curvature can develop non-coplanar spin order in which spin polarization axes at different position span finite solid angles. We find spin chirality can emerge in this setting by doping or adding gauge flux on top of a collinear ferromagnet. This result supports the prediction of spin chirality occurring through an emergent spin orbital interaction. Meanwhile, our result shows that, on top a ferromagnetic background, the spin chirality emerges at a finite threshold value of orbital magnetization, resembling the predicted behavior in theory.