Photocontrol of spin scalar chirality in centrosymmetric itinerant magnets

Abstract

Noncoplanar magnetic structures, such as magnetic skyrmions, are characterized by the 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 sign of the scalar chirality can be controlled by circularly polarized light. Furthermore, magnetic skyrmions are excited after the pulse decays. A photoinduced non-thermal electron distribution plays an important role for instability towards the spin-scalar-chiral state as well as the 120 • Néel state, depending on the next-nearest-neighbor transfer integral. These results provide an alternative route to controlling the spin chirality by photoirradiation.