Light-Induced Anisotropic Skyrmion and Stripe Phases in a Rashba Ferromagnet

An external off-resonant pumping is proposed as a tool to control the Dzyaloshinskii-Moriya interaction (DMI) in ferromagnetic layers with strong spin-orbit coupling. Combining theoretical analysis with numerical simulations for an $s\text{−}d$-like model, we demonstrate that linearly polarized off-resonant light may help stabilize novel noncollinear magnetic phases by inducing a strong anisotropy of the DMI. We also investigate how with the application of electromagnetic pumping one can control the stability, shape, and size of individual Skyrmions to make them suitable for potential applications.

Figure 1

Elliptic Skyrmion arising in the presence of the DMI anisotropy induced by the linearly polarized light. The figure represents the results of our numerically simulations for the model of Eq. (11) at $H_{\text{ext}}=0.01J$ and $\gamma =1.5$ for the DMI strength fixed at $D_x=D_y=0.18J$ for $\gamma =0$. Arrows indicate the in-plane components of the average magnetization in a block of $3\times 3$ spins.

Figure 2

(a) Region of metastability of an isolated Skyrmion in the model of Eq. (11) with the anisotropic DMI strength given by Eq. (10). (b) Phase diagram as a function of the parameter $\gamma$ and external magnetic field $H_{\text{ext}}$. Both figures represent the results of numerical simulations of the model of Eq. (11) with the DMI strength given by $D_x=D_y=0.18J$ at $\gamma =0$.