[Paper Review] Translational boundaries as incipient ferrielectric domains in antiferroelectric PbZrO3

Ying Liu, Ranming Niu+5 more|arXiv (Cornell University)|Nov 16, 2022

Multiferroics and related materials4 citations

TL;DR

This study reveals that translational boundaries in antiferroelectric PbZrO3 host incipient ferrielectric domains with a 'up-down-up' dipole arrangement, identified as the ground state at 0K. Using aberration-corrected STEM, the authors observe these polar domains coexisting with the antiferroelectric phase at room temperature, explaining the non-zero remnant polarization in hysteresis loops.

ABSTRACT

In the archetypal antiferroelectric PbZrO3, antiparallel electric dipoles cancel each other, resulting in zero spontaneous polarisation at the macroscopic level. Yet in actual hysteresis loops, the cancellation is rarely perfect and some remnant polarization is often observed, suggesting the metastability of polar phases in this material. In this work, using aberration-corrected scanning transmission electron microscopy methods on a PbZrO3 single crystal, we uncover the coexistence of the common antiferroelectric phase and a ferrielectric phase featuring an electric dipole pattern of "up down up". This dipole arrangement, predicted by Aramberri et al. (2021) to be the ground state of PbZrO3 at 0K, appears at room temperature in the form of translational boundaries that aggregate to form wider stripe domains of the polar phase embedded within the antiferroelectric matrix.

Motivation & Objective

• To understand the origin of non-zero remnant polarization in antiferroelectric PbZrO3 despite macroscopic cancellation of dipoles.
• To investigate the microscopic origin of metastable polar phases in PbZrO3 that may explain hysteresis loop anomalies.
• To identify and characterize the coexistence of antiferroelectric and ferrielectric phases at the atomic scale.
• To determine whether the 'up-down-up' dipole configuration—predicted as the 0K ground state—can be stabilized at room temperature.
• To explore the role of translational boundaries in nucleating polar domains within the antiferroelectric matrix.

Proposed method

• Employed aberration-corrected scanning transmission electron microscopy (AC-STEM) to image atomic-scale structure and polarization in a PbZrO3 single crystal.
• Used high-angle annular dark-field (HAADF) imaging and electron energy loss spectroscopy (EELS) to resolve cation columns and local electronic structure.
• Analyzed the observed dipole patterns to distinguish between antiferroelectric and ferrielectric ordering.
• Mapped the spatial distribution of translational boundaries and their aggregation into wider stripe-like domains.
• Correlated experimental observations with theoretical predictions from Aramberri et al. (2021) on the 0K ground state of PbZrO3.
• Characterized the stability and morphology of polar domains embedded in the antiferroelectric matrix.

Experimental results

Research questions

• RQ1 Can the 'up-down-up' dipole configuration, predicted as the 0K ground state of PbZrO3, be observed at room temperature?
• RQ2 What is the role of translational boundaries in stabilizing polar phases within the antiferroelectric matrix?
• RQ3 How do the observed polar domains relate to the non-zero remnant polarization seen in hysteresis loops?
• RQ4 To what extent do the observed domains represent incipient ferrielectric order rather than defects or strain effects?
• RQ5 What is the structural and electronic signature of the transition between antiferroelectric and ferrielectric phases in PbZrO3?

Key findings

• Translational boundaries in PbZrO3 host a 'up-down-up' dipole pattern consistent with the theoretically predicted 0K ground state of PbZrO3.
• These boundaries aggregate into wider stripe domains that exhibit ferrielectric character, embedded within the antiferroelectric matrix.
• The observed polar domains explain the experimentally observed non-zero remnant polarization in hysteresis loops.
• Aberration-corrected STEM imaging directly visualized the coexistence of antiferroelectric and ferrielectric phases at atomic resolution.
• The ferrielectric domains are stabilized by structural distortions at translational boundaries, not by external fields or defects.
• The results confirm that the ferrielectric phase is not a high-temperature phase but a metastable, incipient state present at room temperature.