Dynamic motion of individual polar skyrmion under stress gradient: a phase-field simulation

Polar skyrmions, as topologically protected nanostructures, hold great promise for next-generation nanoelectronic devices. However, the controlled dynamic motion of individual skyrmions in ferroelectrics, particularly their driving mechanisms, remains challenging. Using phase-field simulations, this study systematically investigated the stress-gradient-driven directional motion of a single polar skyrmion. The results demonstrate that a stress gradient can effectively drive the skyrmion towards regions of higher stress. The skyrmion's velocity shows a linear relationship with the stress gradient magnitude, while its mobility exhibits a parabolic monotonic decrease with increasing local stress. A quantitative model was established, revealing that the velocity is governed by the coupled effects of local stress and the stress gradient. This motion is identified as a spontaneous process driven by the reduction of the system's total free energy. Our findings provide an important theoretical foundation for developing stress-field-controlled nanoelectronic devices.