2025/04/15 by Rein Liefferink, Liefferink, Rein, Lukas Körber +9 · 2 citations
Physics and Astronomy · Engineering · #Laser-Matter Interactions and Applications #Laser Material Processing Techniques #Magnetic properties of thin films
paper · doi:10.48550/arxiv.2504.11013
Laser-induced ultrafast skyrmion nucleation has been experimentally demonstrated in several materials. So far, atomistic models have been used to corroborate experimental results. However, such simulations do not provide a simple intuitive understanding of the underlying physics. Here, we propose a coarse-grained effective theory where skyrmions can be nucleated or annihilated by thermal activation over energy barriers. Evaluating these two processes during a heat pulse shows good agreement with atomistic spin dynamics simulations and experiments while drastically reducing computational complexity. Furthermore, the effective theory provides a direct guide for experimentally optimizing the number of nucleated skyrmions. Interestingly, the model also predicts a novel pathway for ultrafast annihilation of skyrmions. Our results pave the way for a deeper understanding of ultrafast strongly nonequilibrium dynamics in magnetism and can generalize to ultrafast phase transitions in other long-range ordered systems.