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.