Effect of uniaxial compressive stress on polarization switching and domain wall formation in tetragonal phase BaTiO3 via machine learning potential

• Mechanical stress–induced polarization switching and domain wall formation in BaTiO 3 were investigated using a machine learning potential. • Domain wall formation was found to depend on supercell size through the activation energy of polarization switching. • The BaTiO 3 hysteresis loop was successfully reproduced, and stress-induced double hysteresis loops were observed. Ferroelectric materials such as BaTiO 3 exhibit spontaneous polarization that can be reoriented by an external electric field, forming the basis of a wide range of memory, actuator, and sensor applications. However, the polarization switching behavior is strongly influenced by mechanical boundary conditions due to the intrinsic electromechanical coupling in ferroelectrics. In this study, we employ a machine learning interatomic potential to investigate the effect of uniaxial compressive stress on polarization switching and domain wall evolution in the tetragonal phase of BaTiO 3 . This study revealed that a critical stress of approximately 120 MPa, above which 90° polarization switching occurs. Beyond the critical stress, larger supercells exhibit lower activation energies for polarization switching, accompanied by the 180° domain wall formation and reduced constraints from periodic boundary conditions, thereby facilitating domain-wall formation. Moreover, increasing compressive stress leads to a reduction in both the remnant polarization and the coercive field, while a double hysteresis loop emerges at a stress level of 80 MPa. These findings provide atomistic insights into stress-controlled ferroelectric switching and highlight the crucial role of mechanical loading in designing reliable ferroelectric devices.