Strong Room-Temperature Ferroelectricity in Strained SrTiO3 Homoepitaxial Film

Although the discovery of exceptional ferroelectricity in paraelectrics offers great opportunities to enrich the diversity of the ferroelectric family and promote the development of novel functionalities, transformation of paraelectric phases into ferroelectric phases remains challenging. Herein, a method is presented for driving paraelectrics into ferroelectric states via the introduction of M/O-deficient (M for metal) perovskite nanoregions. Using this method, strong ferroelectricity, equivalent to that of classic ferroelectrics, is achieved in a prototype paraelectric strontium titanate (SrTiO3) homoepitaxial film embedded with Ti/O-deficient perovskite nanoregions. It is shown that these unique nanoregions impose large out-of-plane tensile strain and electron-doping effects on the matrix to form a tetragonal structure (tetragonality = 1.038), driving the off-center movements of Ti and Sr atoms. This leads to a significant room-temperature ferroelectric polarization (maximum polarization = 41.6 mu C cm(-2) and spontaneous polarization = 25.2 mu C cm(-2) at 1.60 MV cm(-1)) with a high thermal stability (T-stable approximate to 1098 K). The proposed approach can be applied to various paraelectrics for creating ferroelectricity and generating emergent physical properties, opening the door to a new realm of materials design.

Automated summary

The study presents a method for driving paraelectrics into ferroelectric states by introducing M/O-deficient perovskite nanoregions, successfully achieving strong ferroelectricity in a prototype paraelectric strontium titanate homoepitaxial film. This method paves the way for creating ferroelectricity in various paraelectrics and generating emergent physical properties, opening up new possibilities in material design.