固体电介质中的挠曲电效应

Flexoelectric Effect in Solid Dielectrics

挠曲电效应通常描述为非均匀变形如应变梯度引起的电极化或者电场梯度引起的变形.应变梯度能够局部破坏晶体的反演对称从而在材料中诱导电极化,因此挠曲电效应是固体电介质材料中普遍存在的一种力电耦合效应.应变梯度和电场梯度均随材料尺寸的减小而迅速增大,在宏观尺度通常被忽略的挠曲电效应在微纳尺度反而起着非常重要的作用,会显著影响材料的物理性能.与压电效应和电致伸缩效应相比,挠曲电效应具有独特的尺寸依赖特征,其不受材料对称性和铁电材料居里相变温度的限制.论文综述了固体电介质中的挠曲电效应,并重点从理论、材料和应用方面综述了固体电介质中挠曲电效应的研究进展,对挠曲电效应的独特性能进行了详细地讨论,最后论文展望了固体电介质中挠曲电效应相关研究的开放性问题和发展方向.

The flexoelectric effect in solid dielectrics refers to the elastic-strain-gradient-generated electric polarization,or the elastic deformation induced by an electric field strain.Since the strain gradient can locally break the inversion symmetry of materials,the flexoelectric effect is a universal electromechanical coupling effect in solid dielectrics.The flexoelectric effect is inversely proportional to the scale of materials due to the strain gradient and electric field gradient;therefore,it becomes significant or even dominant in the overall physical properties of materials at the nanoscale.Compared with piezoelectric effect and electrostrictive effect,the flexoelectric effect has the unique size effect characteristics.Moreover,the flexoelectric effect is not limited by the symmetry of materials or the Curie phase transition temperature of ferroelectric materials.This work reviewed the flexoelectric effect in solid dielectrics,especially on the theoretical and experimental understanding of it in solid dielectrics.In addition,a perspective on the future directions of the flexoelectric effect in solid dielectrics is provided to discuss the flexoelectric effect in materials.