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Strong Room‐Temperature Ferroelectricity in Strained SrTiO 3 Homoepitaxial Film
Author(s) -
Li Tianyu,
Deng Shiqing,
Liu Hui,
Sun Shengdong,
Li Hao,
Hu Shuxian,
Liu Shi,
Xing Xianran,
Chen Jun
Publication year - 2021
Publication title -
advanced materials
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 10.707
H-Index - 527
eISSN - 1521-4095
pISSN - 0935-9648
DOI - 10.1002/adma.202008316
Subject(s) - ferroelectricity , materials science , dielectric , tetragonal crystal system , condensed matter physics , polarization (electrochemistry) , perovskite (structure) , optoelectronics , crystallography , crystal structure , chemistry , physics
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 (SrTiO 3 ) 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 µC cm −2 and spontaneous polarization = 25.2 µC cm −2 at 1.60 MV cm −1 ) with a high thermal stability ( T stable ≈ 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.