Zeeman coupling and Dzyaloshinskii-Moriya interaction driven by electric current vorticity

藤本 純治*; 小椎八重 航*; 松尾 衛; 前川 禎通

Physical Review B, 103(22), p.L220402_1 - L220402_5, 2021/06

https://doi.org/10.1103/PhysRevB.103.L220402

The Dzyaloshinskii-Moriya interaction, i.e., antisymmetric exchange interaction, combined with a Zeeman magnetic field gives rise to various magnetic states such as chiral, helical, and skyrmionic states. This interaction conventionally originates from spin-orbit coupling and thus needs somewhat heavy elements. In contrast, we here show a Dzyaloshinskii-Moriya interaction which is driven by electric current vorticity. We also find that the vorticity acts on localized spins as a Zeeman field, which may explain a recent experiment on current-driven magnetic skyrmion creation and annihilation without an external magnetic field in a device with a notch structure in FeGe. The theory explains the control of skyrmion creation and annihilation by current direction and opens different possibilities for studies of magnetic textures by using structural settings.