Epitaxial-strain-induced polar-to-nonpolar transitions in layered oxides.
Epitaxial-strain-induced polar-to-nonpolar transitions in layered oxides.
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DOI：
10.1038/nmat4664
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发表时间：
2016-09
期刊：
影响因子：
41.2
通讯作者：
Xuezeng Lu;J. Rondinelli
中科院分区：
文献类型：
--
作者：
Xuezeng Lu;J. Rondinelli
外延应变可以在复合氧化物薄膜中诱导聚集现象和新的功能。应变和极性晶格模式之间的强耦合可以稳定新的铁电相，从非极性取向或提高电极化和居里温度。最近，应变也被用来诱导新的金属-绝缘体的转变，和磁重建，，通过其耦合到非极性模式，包括BO 6过渡金属八面体的旋转。虽然大的应变被认为是诱导铁电性，在这里，我们证明了一个极性到非极性的转变，在（001）薄膜的层状A3 B2 O 7混合不正常铁电体与实验可访问的双轴应变。我们表明，起源的过渡起源于三线性相关的晶格模式的相互作用，在层状氧化物中活跃的相互作用，这些相互作用是直接应变可调。我们的研究结果要求仔细重新检查的作用，在铁电薄膜与非平凡的非谐性的应变极化耦合，并提供了一条路线，以寻找新的功能在层状氧化物。
Epitaxial strain can induce collective phenomena and new functionalities in complex oxide thin films. Strong coupling between strain and polar lattice modes can stabilize new ferroelectric phases from nonpolar dielectrics or enhance electric polarizations and Curie temperatures. Recently, strain has also been exploited to induce novel metal–insulator transitions,and magnetic reconstructions,,,through its coupling to nonpolar modes, including rotations of BO6transition-metal octahedra. Although large strains are thought to induce ferroelectricity, here we demonstrate a polar-to-nonpolar transition in (001) films of layered A3B2O7hybrid-improper ferroelectrics with experimentally accessible biaxial strains. We show the origin of the transition originates from the interplay of trilinear-related lattice mode interactions active in the layered oxides, and those interactions are directly strain tunable. Our results call for a careful re-examination of the role of strain–polarization coupling in ferroelectric films with nontrivial anharmonicities and offer a route to search for new functionalities in layered oxides.