Benedek Nicole A, Rondinelli James M, Djani Hania, Ghosez Philippe, Lightfoot Philip
Materials Science and Engineering Program, The University of Texas at Austin, 1 University Station, Austin, Texas 78712, USA.
Dalton Trans. 2015 Jun 21;44(23):10543-58. doi: 10.1039/c5dt00010f. Epub 2015 Feb 17.
ABO(3) perovskites have fascinated solid-state chemists and physicists for decades because they display a seemingly inexhaustible variety of chemical and physical properties. However, despite the diversity of properties found among perovskites, very few of these materials are ferroelectric, or even polar, in bulk. In this Perspective, we highlight recent theoretical and experimental studies that have shown how a combination of non-polar structural distortions, commonly tilts or rotations of the BO(6) octahedra, can give rise to polar structures or ferroelectricity in several families of layered perovskites. We discuss the crystal chemical origin of the polarization in each of these families - which emerges through a so-called 'trilinear coupling' or 'hybrid improper' mechanism - and emphasize areas in which further theoretical and experimental investigation is needed. We also consider how this mechanism may provide a generic route for designing not only new ferroelectrics, but also materials with various other multifunctionalities, such as magnetoelectrics and electric field-controllable metal-insulator transitions.
几十年来，ABO₃钙钛矿一直吸引着固态化学家和物理学家，因为它们展现出似乎无穷无尽的化学和物理性质。然而，尽管在钙钛矿中发现了多种多样的性质，但这些材料中只有极少数在体相中是铁电的，甚至是极性的。在这篇综述中，我们重点介绍了最近的理论和实验研究，这些研究表明，非极性结构畸变（通常是BO₆八面体的倾斜或旋转）的组合如何在几个层状钙钛矿家族中产生极性结构或铁电性。我们讨论了这些家族中每一个家族极化的晶体化学起源——它通过所谓的“三线耦合”或“混合非本征”机制出现——并强调了需要进一步进行理论和实验研究的领域。我们还考虑了这种机制如何不仅为设计新型铁电体，而且为设计具有各种其他多功能性的材料（如磁电体和电场可控的金属-绝缘体转变材料）提供一条通用途径。
