Templated perpendicular ferroelectricity in textured Aurivillius oxide-based thin films

The discovery of novel ferroelectric compounds and the modulation of polarization in established ferroelectric materials have persistently represented crucial and highly dynamic areas of research within the field of ferroelectric materials science. Here we demonstrate a structural templating strategy to reconfigure Aurivillius-phase oxides into metastable ferroelectric phases with tailored polarization. By stabilizing a metastable WO₃ phase within a Bi₂WO₆ framework, we achieve robust out-of-plane polarization (10 µC/cm²) in textured WO₃/Bi₂WO₆ films, contrasting the purely in-plane polarization of pristine Bi₂WO₆. First-principles calculations and atomic-resolution scanning transmission electron microscopy unveil a WO₃ phase with oxygen displacement-driven ferroelectricity. Prototype ferroelectric field-effect transistors and memristors fabricated from these films exhibit robust switching ratios (>10⁶) and thermal stability up to 350 °C. This work not only expands the family of binary ferroelectric oxides but also establishes a generalizable paradigm for overcoming polarization-directionality constraints in layered ferroelectrics.