Chirality control of the spin structure in monoaxial helimagnets by charge current

Chirality control of the spin structure in monoaxial helimagnets by using charge current is theoretically investigated. The classical $J1−J2$ Heisenberg model has two degenerate helical states that are characterized by the chirality. In a recent experiment, it has been shown that the chirality of the spin structure can be controlled by applying a charge current during the field-decreasing process [Jiang et al., Nat. Commun. 11, 1601 (2020)]. We reproduced this experiment by numerical calculations based on the Landau–Lifshitz–Gilbert equation with the spin-transfer torque. We show that the damping torque and spin-transfer torque are responsible for the controllability. In addition, we theoretically propose more convenient forms of chirality control: instantaneous switching of chirality and zero-field control by using a ferromagnet junction. Such improved controllability may pave the way to spintronics based on the chirality degree of freedom.