Surprisingly little is known about the microscopic processes that govern ferroelectric switching in orthorhombic ferroelectrics. To study these processes, we combine ab initio-based molecular dynamics simulations and data science on the prototypical material ${\mathrm{BaTiO}}_3$. We reveal two different field regimes: For moderate field strengths, the switching is dominated by domain wall motion, while a fast bulklike switching can be induced for large fields. Switching in both field regimes follows a multistep process via polarization directions perpendicular to the applied field. In the former case, the moving wall is of Bloch character and hosts dipole vortices due to nucleation, growth, and crossing of two-dimensional ${90}^{\circ }$ domains. In the second case, the local polarization shows a continuous correlated rotation via an intermediate tetragonal multidomain state.

• Received 19 October 2023
• Accepted 8 January 2024

DOI:https://doi.org/10.1103/PhysRevMaterials.8.024403