Trochoidal dynamics and pair generation in skyrmion and antiskyrmion dynamics driven by spin-orbit torques

In a collaboration with colleagues at Johannes Gutenberg-Universität Mainz, Uppsala Universitet, and Christian-Albrechts-Universität zu Kiel, we have shown theoretically that skyrmions and antiskyrmions can behave very differently under spin-orbit torques. One key finding is that antiskyrmions can undergo trochoidal motion, which is analogous to Walker breakdown in domain wall dynamics. This threshold defines a speed limit for rectilinear displacement. Another is the onset of skrymion-antiskyrmion pair generation under large damping-like torques, which results in a gas with excess skyrmions. This imbalance in matter-antimatter production is a consequence of the asymmetric dynamics at high energies.

This work recently appeared in Nature Electronics.

Reference: U. Ritzmann, S. von Malottki, J.-V. Kim et al., Nat. Electron. 1, 451–457 (2018).