In-plane quasi-single-domain BaTiO$_3$ via interfacial symmetry engineering

TL;DR

This paper demonstrates a method to stabilize in-plane quasi-single-domain ferroelectric BaTiO$_3$ thin films through interfacial symmetry engineering and strain, enabling improved optoelectronic device performance.

Contribution

It introduces a novel approach combining interfacial symmetry and anisotropic strain to achieve single-domain in-plane polarization in ferroelectric thin films.

Findings

Theoretical calculations highlight the role of substrate interfacial environment.

Experimental evidence confirms stabilization of in-plane quasi-single-domain polarization.

Design principles for ferroelectric domain engineering are established.

Abstract

The control of the in-plane domain evolution in ferroelectric thin films is not only critical to understanding ferroelectric phenomena but also to enabling functional device fabrication. However, in-plane polarized ferroelectric thin films typically exhibit complicated multi-domain states, not desirable for optoelectronic device performance. Here we report a strategy combining interfacial symmetry engineering and anisotropic strain to design single-domain, in-plane polarized ferroelectric BaTiO$_3$ thin films. Theoretical calculations predict the key role of the BaTiO$_3$ / PrScO$_3$ (110)$_O$ substrate interfacial environment, where anisotropic strain, monoclinic distortions, and interfacial electrostatic potential stabilize a single-variant spontaneous polarization. A combination of scanning transmission electron microscopy, piezoresponse force microscopy, ferroelectric hysteresis loop measurements, and second harmonic generation measurements directly reveals the stabilization of the in-plane quasi-single-domain polarization state. This work offers design principles for engineering in-plane domains of ferroelectric oxide thin films, which is a prerequisite for high performance optoelectronic devices.