Templated perpendicular ferroelectricity in textured Aurivillius oxide-based thin films

Area of Science:

• Materials Science
• Solid State Physics
• Nanotechnology

Background:

• Ferroelectric materials are crucial for electronic devices.
• Controlling polarization direction in ferroelectrics is a key research challenge.
• Aurivillius-phase oxides are a class of ferroelectric materials with layered structures.

Purpose of the Study:

• To develop a structural templating strategy to reconfigure Aurivillius-phase oxides into metastable ferroelectric phases.
• To achieve tailored polarization in ferroelectric films.
• To expand the family of ferroelectric oxides and overcome polarization-directionality constraints.

Main Methods:

• Structural templating strategy using a Bi2WO6 framework.
• Stabilization of a metastable WO3 phase.
• First-principles calculations and atomic-resolution scanning transmission electron microscopy.
• Fabrication of prototype ferroelectric field-effect transistors and memristors.

Main Results:

• Achieved robust out-of-plane polarization (10 µC/cm²) in textured WO3/Bi2WO6 films.
• Identified a WO3 phase with oxygen displacement-driven ferroelectricity.
• Demonstrated robust switching ratios (>10⁶) and thermal stability up to 350°C in prototype devices.

Conclusions:

• The structural templating strategy successfully creates metastable ferroelectric phases with tailored polarization.
• This approach expands the family of binary ferroelectric oxides.
• Establishes a generalizable paradigm for overcoming polarization-directionality constraints in layered ferroelectrics.