Proton transfer ferroelectricity/multiferroicity in rutile oxyhydroxides.

Area of Science:

• Materials Science
• Solid-State Physics
• Mineralogy

Background:

• Oxyhydroxide minerals (e.g., FeOOH) are studied for Earth's interior and oxygen electrocatalysis.
• Ferroelectric and multiferroic materials are crucial for advanced electronic applications.

Purpose of the Study:

• To provide first-principle evidence for a new class of ferroelectric/multiferroic oxyhydroxides.
• To investigate the properties and potential applications of these earth-abundant minerals.

Main Methods:

• First-principle calculations were used to identify and characterize new ferroelectric/multiferroic materials.
• Analysis of distorted rutile structures, polarization, piezoelectric coefficients, and Curie temperature (TC).

Main Results:

• Identified β-CrOOH (guyanaite), ε-FeOOH, β-GaOOH, and InOOH as ferroelectric with significant polarization (up to 24 μC cm-2) and piezoelectricity.
• Atomic-thick layers exhibit stable vertical polarization due to O-HO bonds.
• β-CrOOH shows tunable type-I and type-II multiferroicity with potential magnetoelectric coupling.

Conclusions:

• These earth-abundant oxyhydroxides represent a new class of ferroelectrics and multiferroics.
• Potential for constructing heterostructures with metal dioxides for applications in ferroelectric field-effect transistors and multiferroic tunneling junctions.