Supercritical CO₂-Stabilized Room-Temperature Ferroelectricity in 2D Quantum SrTiO₃

Area of Science:

• Materials Science
• Condensed Matter Physics
• Quantum Materials

Background:

• Plastic deformation in quantum materials can induce novel electronic states and structures.
• Strontium titanate (SrTiO3) is a quantum paraelectric material where ferroelectric order is suppressed by quantum fluctuations.
• Stabilizing ferroelectric order in SrTiO3 presents a significant challenge.

Purpose of the Study:

• To achieve ferroelectricity in two-dimensional (2D) SrTiO3.
• To explore plastic deformation as a method for manipulating electronic properties in quantum materials.
• To investigate the role of supercritical carbon dioxide in inducing and stabilizing ferroelectricity.

Main Methods:

• Inducing plastic deformation in SrTiO3 nanosheets using supercritical carbon dioxide (SC CO2).
• Characterizing the structural and electronic changes in SrTiO3 nanosheets.
• Measuring ferroelectric properties, including polarization reversal and maximum polarization.

Main Results:

• Successfully achieved ferroelectricity in 2D SrTiO3 via SC CO2-induced plastic deformation.
• Observed "plastic behavior" in SrTiO3 nanosheets, with CO2 inducing and stabilizing atomic dislocations.
• Demonstrated robust room-temperature ferroelectricity with 180° polarization reversal and a maximum polarization of 30.153 µC cm⁻².

Conclusions:

• Plastic deformation using SC CO2 is a viable route to stabilize ferroelectric order in 2D SrTiO3.
• This technique offers a new method for manipulating the electronic properties of quantum materials.
• The findings open avenues for designing novel electronic devices based on ferroelectric quantum materials.