Static and dynamic characteristics of polar kinks mediated by electrical and mechanical conditions

Polar kinks, as a kind of polarization soliton, play crucial roles in polarization switching, domain wall motion, and other dynamics in ferroelectric materials. However, the static and dynamic characteristics of polar kinks are poorly understood so far, hindering the potential device design based on such polar structure. Here, via dynamical phase-field simulations, we present a comprehensive study on the static and dynamic characteristics of polar kinks at the 180\ifmmode^\circ\else\textdegree\fi{} domain walls of $\mathrm{BaTi}{\mathrm{O}}_{3}$ films under different electrical and mechanical conditions. Intriguing phenomena of polar kinks including generation and annihilation, solitonlike motion, kink-(anti)kink interaction, as well as topological transformation among kink, antikink, and flux closure are revealed. An extended generalized configurational force framework is proposed to obtain the driving force of the polar kinks. Under this framework, the equation of motion of polar kinks is derived by integrating the field configurations and can well capture the quasi-one-dimensional motion of polar kinks. Moreover, the concept of toroidal driving moment is adopted to understand the strain-induced topological transformation related to polar kinks. These results demonstrate the prominent and controllable soliton characteristics of polar kinks and provide useful insights for potential applications in logic devices.