Thermally driven stochastic magnetic-state selection and competing skyrmion annihilation pathways

We investigate current-driven skyrmion nucleation and annihilation in confined Ir/Co/Pt nanodots, focusing on the role of thermal fluctuations. While minimum-energy approaches predict well-defined transition mechanisms, we show that finite-temperature dynamics can lead to distinct magnetic configurations under identical nominal conditions. Micromagnetic simulations including spin-transfer torques, Oersted fields, and thermal noise reveal stochastic variability in the current-driven magnetic response, while preserving reproducible current-dependent magnetic regimes across independent thermal-noise realisations. Comparison with geodesic nudged elastic band (GNEB) calculations identifies two competing skyrmion annihilation mechanisms, namely interior collapse and boundary-mediated annihilation, with markedly different activation barriers. At T = 300 K, the corresponding maximum barriers are approximately 44.7 k B T and 21.2 k B T , respectively, indicating that boundary-mediated annihilation is strongly kinetically favoured under thermal activation. These results highlight the interplay between energy landscape topology and stochastic dynamics, providing new insight into current-driven skyrmion transitions in confined geometries.