Reversible to Irreversible Transitions in Periodically Driven Skyrmion Systems

TL;DR

This study investigates the transition from reversible to irreversible motion in periodically driven skyrmion systems, revealing a phase transition characterized by diverging timescales and influenced by the Magnus term, with implications for skyrmion-based applications.

Contribution

It demonstrates a reversible-irreversible transition in skyrmion systems with a critical behavior similar to directed percolation universality class, highlighting the role of the Magnus term.

Findings

Power law divergence of characteristic time near critical drive period

Transition resembles an absorbing phase transition in directed percolation

Magnus term enhances irreversible behavior by increasing accessible orbits

Abstract

We examine skyrmions driven periodically over random quenched disorder and show that there is a transition from reversible motion to a state in which the skyrmion trajectories are chaotic or irreversible. We find that the characteristic time required for the system to organize into a steady reversible or irreversible state exhibits a power law divergence near a critical ac drive period, with the same exponent as that observed for reversible to irreversible transitions in periodically sheared colloidal systems, suggesting that the transition can be described as an absorbing phase transition in the directed percolation universality class. We compare our results to the behavior of an overdamped system and show that the Magnus term enhances the irreversible behavior by increasing the number of dynamically accessible orbits. We discuss the implications of this work for skyrmion applications involving the long time repeatable dynamics of dense skyrmion arrays.