Photocontrol of spin scalar chirality in centrosymmetric itinerant magnets

Abstract: Noncoplanar magnetic structures, such as magnetic skyrmions, are characterized by spin chirality and usually favored by antisymmetric exchange interactions in noncentrosymmetric magnets. Here, we show that a linearly polarized electric-field pulse stabilizes a nonequilibrium spin scalar chiral state in a centrosymmetric itinerant ferromagnet. The scalar chirality has a nonmonotonic dependence on the electric-field strength, and its sign can be controlled by circular polarization. Furthermore, magnetic skyrmions are excited after the pulse decays. A photoinduced nonthermal electron distribution plays an important role for instability towards the spin scalar chiral state as well as the $120^{\circ}$ N\'eel state, depending on the next-nearest-neighbor transfer integral. These results provide an alternative route to controlling spin chirality by photoirradiation.