Liberating a hidden antiferroelectric phase with interfacial electrostatic engineering

Abstract

Antiferroelectric materials have seen a resurgence of interest because of proposed applications in a number of energy-efficient technologies. Unfortunately, relatively few families of antiferroelectric materials have been identified, precluding many proposed applications. Here, we propose a design strategy for the construction of antiferroelectric materials using interfacial electrostatic engineering. We begin with a ferroelectric material with one of the highest known bulk polarizations, BiFeO 3 . By confining thin layers of BiFeO 3 in a dielectric matrix, we show that a metastable antiferroelectric structure can be induced. Application of an electric field reversibly switches between this new phase and a ferroelectric state. The use of electrostatic confinement provides an untapped pathway for the design of engineered antiferroelectric materials with large and potentially coupled responses.

Emergent Antipolar Phase in BiFeO3–La0.7Sr0.3MnO3 Superlattice

“…The LBFO is close to an orthorhombic–rhombohedral ( R 3 c–Pbnm ) morphotropic phase boundary (MPB). A similar antiferroelectric structure was also observed in superlattices of BFO–LaFeO 3 (BFO–LFO) by strain engineering and BFO–LBFO grown on TbScO 3 (TSO) substrates by tuning the electrostatic field. − To determine if the structures observed in Figure are a result of La incorporation in the BFO layers (due to unintentional diffusion from the LSMO layer), energy-dispersive X-ray spectroscopy (EDS) was performed in STEM to provide elemental compositional analysis, along the different BFO–LSMO layers (Figure S3). This EDS profile shows there is negligible La content in the BFO compared with 22% in the LBFO of Morozovska et al, confirming that the BFO lamellar structure is not an accidental La doping–diffusion process but rather due to epitaxial engineering.…”

Physics-Guided Descriptors for Prediction of Structural Polymorphs

“…In Figure c we present views of the structures along the pseudocubic orientations and the structures that could be experimentally observed by using high-resolution transmission electron microscopy. In particular, we see that for the view down the c -axis in-plane a “2up–2down” displacement pattern of the Bi cations appears along the [100] direction, reminiscent of the recently discovered antiferroelectric Pnma phase …”

“…In particular, we see that for the view down the c -axis in-plane a “2up–2down” displacement pattern of the Bi cations appears along the [100] direction, reminiscent of the recently discovered antiferroelectric Pnma phase. 29 …”

“…Several metastable phases have been established computationally, many with larger unit cells . Furthermore, the experimental stabilization of many new phases of BFO − motivates our choice of BFO both to test the predictive power of the method and to identify new metastable phases for future experimental study.…”

Ultrahigh Ferroelectric and Piezoelectric Properties in BiFeO3–BaTiO3 Epitaxial Films Near Morphotropic Phase Boundary

“…Lead-free ferroelectrics are highly desirable for their environment-friendly nature and broad applications in ferroelectric random access memory, surface acoustic wave devices, and transducers, to name a few. Studies on the ferroelectric BaTiO 3 and multiferroic BiFeO 3 have flourished over the past several decades due to their appealing application prospects. − Recently, solid solutions combining BiFeO 3 and BaTiO 3 (BF–BT) have been studied to further modify their electrical performance and exploit new functionalities.…”