The atomic-scale domain wall structure and motion in HfO₂-based ferroelectrics: A first-principle study

The HfO₂-based ferroelectrics have aroused considerable attention due to their potential application in silicon process-compatible memory devices. However, the ferroelectricity origin and the domain evolution have not yet been well understood. It is now generally accepted the orthorhombic Pca2₁ phase is one of ferroelectric phases for HfO₂. In this work, by performing density functional theory calculations, we systematically studied the domain wall structures and evolution based on the Pca2₁ ferroelectric phase. More specifically, the atomic structures of ten types of possible 180° and 90° ferroelectric domain walls are predicted and explored. And the motion of certain domain walls is expected as the microscopic mechanisms of the polarization switching and ferroelectricity activation of Pca2₁ HfO₂ under external electric field. Our results are in good agreement with the recent experimental results on ferroelectric domain walls in HfO₂-based epitaxial thin-film and are helpful to understand the ferroelectricity origin of the HfO₂-based ferroelectrics.