Non-volatile electric-field control of inversion symmetry

Area of Science:

• Materials Science
• Condensed Matter Physics
• Solid State Chemistry

Background:

• Phase boundaries often exhibit competing ground states with distinct crystal symmetries, leading to property changes under stimuli.
• Stabilizing and controlling the coexistence of symmetry-distinct phases is a significant scientific challenge.

Purpose of the Study:

• To stabilize and control the mixed-phase coexistence of centrosymmetric and non-centrosymmetric bismuth ferrite (BiFeO3) phases at room temperature.
• To investigate the effect of electric fields on phase interconversion and material properties.

Main Methods:

• Utilized BiFeO3 layers confined within dielectric TbScO3 layers as a model system.
• Applied orthogonal in-plane electric fields to induce reversible phase interconversion.
• Characterized changes in non-linear optical response, resistivity, and polar order.

Main Results:

• Successfully stabilized mixed-phase BiFeO3 with antipolar (centrosymmetric) and polar semiconducting (non-centrosymmetric) behaviors.
• Demonstrated reversible, non-volatile interconversion between phases using electric fields, controlling centrosymmetry.
• Observed significant changes: >3 orders of magnitude in non-linear optical response and >5 orders of magnitude in resistivity.
• Showcased electric field-induced polarization erasure due to anisotropic octahedral tilts.

Conclusions:

• Established a platform for cross-functional devices by exploiting tunable optical, electrical, and ferroic responses.
• Highlighted octahedral tilts as a critical order parameter in designing material interfaces for advanced functionalities.