TITLE: Releasing the capabilities of perpendicular switching in layered oxides
AUTHOR: Sergio Puebla, Department of Materials Science and Engineering, University of California, Berkeley, Berkeley, CA, USA & ex-2D Foundry at ICMM
WHEN: October, 16 - 12PM
WHERE: Sala de Seminarios
ABSTRACT: Layered ferroelectrics offer opportunities to control polarization through structural distortions and mechanical boundary conditions. Bi₄Ti₃O₁₂ (BiTO), an Aurivillius oxide with predominantly in-plane polarization, provides a platform for studying these effects in thin films and membranes.
I will first present our demonstration of perpendicular polarization switching in epitaxial BiTO films [1]. A field applied normal to the film reverses the in-plane polarization through trilinear coupling between orthogonal polarization components and an antipolar distortion associated with oxygen-octahedral tilts and rotations. First-principles calculations and structural and polarization-sensitive measurements establish a mechanism for controlling the dominant polarization component using a transverse electric field.
I will then discuss ongoing work on substrate-clamped BiTO films grown on substrates with different lattice mismatch along with freestanding membranes. Structural and functional studies are carried on clamped and freestanding samples and we will discuss how realising this material produces a distinctive response.
These comparisons clarify how strain, mechanical clamping and domain configuration influence the ferroelectric response, with the main changes arising when Aurivillious films become freestanding.
Bibliography:
[1] Gupta, P., Puebla, S., Gómez-Ortiz, F. et al. Perpendicular switching of polarization in layered ferroelectrics. Nature 656, 67–72 (2026). https://doi.org/10.1038/s41586-026-10839-3
