论文标题
直接可视化晶体中不可还原的铁晶
Direct Visualization of Irreducible Ferrielectricity in Crystals
论文作者
论文摘要
在固体中，电荷极性可以一对一地对应于旋转极性在现象学上，例如铁电/铁磁性，抗fiferroelelectricition/抗铁磁性，甚至偶极涡流/磁性涡流，但是铁晶/屈光度不断地以微观水平讲述一个截然不同的故事。由于电荷偶极子的定义涉及多个离子，因此偶极子单元可能有多种选择，这使得大多数超级级别的订单等同于铁电的订单，即，这种铁晶体不是真正的独立分支。在这项工作中，通过使用球形像差校正的扫描透射电子显微镜，我们可以在BAFE2SE3中可视化非平凡的Ferrielectric结构性演变，其中两个极性子层的发展是不同步的，为此我们称其为不可降低的Ferrielecelectricity。这种不可约合的铁晶导致了依赖温度依赖性极化的非单调行为，甚至在有序状态下的补偿点。我们的发现明确区分了固体中的铁晶与铁电的分歧。
In solids, charge polarity can one-to-one correspond to spin polarity phenomenologically, e.g. ferroelectricity/ferromagnetism, antiferroelectricity/antiferromagnetism, and even dipole-vortex/magnetic-vortex, but ferrielectricity/ferrimagnetism kept telling a disparate story in microscopic level. Since the definition of a charge dipole involves more than one ion, there may be multiple choices for a dipole unit, which makes most ferrielectric orders equivalent to ferroelectric ones, i.e. this ferrielectricity is not necessary to be a real independent branch of polarity. In this work, by using the spherical aberration-corrected scanning transmission electron microscope, we visualize a nontrivial ferrielectric structural evolution in BaFe2Se3, in which the development of two polar sub-lattices is out-of-sync, for which we term it as irreducible ferrielectricity. Such irreducible ferrielectricity leads to a non-monotonic behavior for the temperature-dependent polarization, and even a compensation point in the ordered state. Our finding unambiguously distinguishes ferrielectrics from ferroelectrics in solids.
