Ferroelectric Translational Boundaries Separating\nAntiferroelectric Domains in Y‑Doped HfO<sub>2</sub>

Domain\nwalls in complex perovskite oxides are known for their unique\nfunctional properties and potential in electronic devices. Hafnium\noxide (HfO<sub>2</sub>)-based ferroelectric and antiferroelectric\nmaterials, as a simpler transition-metal oxide system compared to\nperovskite-derived complex oxides, have gained significant interest\ndue to their compatibility with silicon electronics and their lead-free\ncomposition, aligning with sustainable development goals. Nevertheless,\nresearch into the functionalities and structural characteristics of\ndomain walls in hafnia is still limited, limiting their applications\nin domain wall electronic devices. In this work, using aberration-corrected\nscanning transmission electron microscopy high-angle annular dark\nfield and integrated differential phase contrast imaging techniques,\nwe revealed three types of translational boundaries (TBs), two with\na phase difference of π and another one with a phase difference\nof π/2. The π TBs (or antiphase boundaries) show either\na ferroelectric phase structure with a 0↑0↑ dipole pattern\nor a monoclinic phase structure, while the π/2 TB shows a reduced\ndipole magnitude. The ferroelectric TB is anticipated to enhance residual\npolarization within the polarization–electric field hysteresis\nloop. Its reversible switching capability indicates significant potential\nfor implementation in domain wall memory devices, which are projected\nto be more energy efficient than traditional ferroelectric domain\nmemories.