Tunable ultrafast dynamics of antiferromagnetic vortices in nanoscale dots

Topological vortex textures in magnetic disks have garnered great attention due to their interesting physics and diverse applications. However, prior studies have primarily focused on microscale ferromagnetic disks with oscillation frequencies limited to the GHz range. To address this critical bottleneck, we propose a novel mechanism to generate vortex states in antiferromagnetic nanodots surrounded by heavy metals, which enables ultrasmall sizes—hundreds to thousands of times smaller in area—and ultrafast frequencies—hundreds to thousands of times higher. We demonstrate that, interestingly, the interfacial Dzyaloshinskii-Moriya interaction (iDMI) induced by the heavy metal at the dot boundary acts as an effective chemical potential for vortices. Analogous to the formation of superfluid vortices through rotation, we show that the iDMI can stabilize a magnetic vortex state. Moreover, applying an electric current induces vortex oscillations via spin-transfer torque, reaching THz frequencies that can be further tuned with external magnetic fields. These theoretical predictions are validated via micromagnetic simulations. Furthermore, we show that coherent coupling between vortices can be achieved via an antiferromagnetic link, which depends on the vortex polarity and topological charge and is also tunable via the vortex resonance frequency. Our proposal overcomes the critical bottleneck and opens a new vortex-based path toward next-generation information technologies and high-density data storage.