Photocontrol of spin scalar chirality in centrosymmetric itinerant magnets

TL;DR

This paper demonstrates that linearly polarized light can induce and control spin scalar chirality in centrosymmetric itinerant magnets, leading to the formation of magnetic skyrmions through nonthermal electron distributions.

Contribution

It introduces a novel method of controlling spin chirality using photoirradiation in centrosymmetric magnets, independent of antisymmetric exchange interactions.

Findings

Linearly polarized pulses stabilize spin scalar chiral states.

Circular polarization controls the chirality sign.

Magnetic skyrmions are generated after pulse decay.

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.