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

Plastic deformation can lead to amount of dislocation that bring new physical phenomena and fascinating structure, so exploring advanced technology to obtain novel electronic states in quantum materials upon proper and efficient manipulation is in significance. Strontium titanate (SrTiO₃) is one of the few known quantum paraelectric materials, in which quantum fluctuations and antiferro-distortive instabilities suppress ferroelectric polar order, resulting in a nonpolar paraelectric state, thus how to stabilize ferroelectric order is very significant and challenging. Herein, the ferroelectricity of two-dimensional (2D) SrTiO₃ has been achieved via plastic deformation induced by supercritical carbon dioxide (SC CO₂). Experiment confirms that SrTiO₃ nanosheets exhibit "plastic behavior", i.e., CO₂ not only bring the atomic dislocation, but also help their stabilization, leading to the formation of robust room temperature ferroelectricity with 180° polarization reversal and significant ferroelectric polarization (maximum polarization = 30.153 µC cm^-2). These results establish a new route to plastic deformation for the manipulation of the electronic properties of quantum materials.