Nonvolatile Electric-Field Control of Inversion Symmetry

TL;DR

This study demonstrates reversible, nonvolatile electric-field control of phase coexistence in BiFeO3 layers, enabling significant changes in optical, electrical, and ferroic properties at room temperature, with potential for advanced device applications.

Contribution

It introduces a method to stabilize and reversibly switch between distinct symmetry phases in BiFeO3 using electric fields, enabling multifunctional property control.

Findings

Reversible phase switching with electric fields at room temperature.

Over three orders of magnitude change in non-linear optical response.

Over five orders of magnitude change in resistivity.

Abstract

In condensed-matter systems, competition between ground states at phase boundaries can lead to significant changes in material properties under external stimuli, particularly when these ground states have different crystal symmetries. A key scientific and technological challenge is to stabilize and control coexistence of symmetry-distinct phases with external stimuli. Using BiFeO3 (BFO) layers confined between layers of the dielectric TbScO3 as a model system, we stabilize the mixed-phase coexistence of centrosymmetric and non-centrosymmetric BFO phases with antipolar, insulating and polar, semiconducting behavior, respectively at room temperature. Application of in-plane electric (polar) fields can both remove and introduce centrosymmetry from the system resulting in reversible, nonvolatile interconversion between the two phases. This interconversion between the centrosymmetric insulating and non-centrosymmetric semiconducting phases coincides with simultaneous changes in the non-linear optical response of over three orders of magnitude, a change in resistivity of over five orders of magnitude, and a change in the polar order. Our work establishes a materials platform allowing for novel cross-functional devices which take advantage of changes in optical, electrical, and ferroic responses.