论文标题
通过延髓替换在CA $ _3 $ _3 $ _2 $ o $ $ _7 $中通过元素映射显示的分层钙钛矿结构的稳定
Stabilization of layered perovskite structures via strontium substitution in Ca$_3$Ti$_2$O$_7$ revealed via elemental mapping
论文作者
论文摘要
已经对分层化合物进行了广泛的研究，从分层的铜层到范德华的材料，这些材料具有关键的生长和堆叠断层。但是，由于实验困难，研究结构的研究较少。我们介绍了ruddlesden-popper ca $ _ {2.46} $ sr $ _ {0.54} $ _2 $ _2 $ o $ $ _7 $的特征性缺陷结构，这表现为表现出杂交不正确的家属。透射电子显微镜表明，在铁电域中引入了许多由7层和15层组成的间隔。元素地图表明，将SR离子选择性地取代为间生长的钙钛矿层。密度功能理论计算支持位于生长间中有利的SR离子的位点选择性取代。可以通过CA和SR离子之间的离子 - 二刺差来解释Ruddlesden-Popper期和通过SR替代之间的稳定。该研究揭示了源自CA $ _ {2.46} $ sr $ _ {0.54} $ _2 $ _2 $ o $ $ _7 $的分层钙钛矿结构的详细缺陷结构，并显示了元素映射在探测氧化物中替代效应时的实用性。
Extensive studies have been performed on layered compounds, ranging from layered cuprates to van der Waals materials with critical issues of intergrowths and stacking faults. However, such structures have been studied less because of experimental difficulty. We present characteristic defect structures of intergrowths in the Ruddlesden-Popper Ca$_{2.46}$Sr$_{0.54}$Ti$_2$O$_7$, which is known to exhibit hybrid improper ferroelectricity. Transmission electron microscopy reveals that numerous intergrowths composed of 7 and 15 layers are introduced in the ferroelectric domains. Elemental maps demonstrate that Sr ions are selectively substituted into the perovskite layers of intergrowths. Density functional theory calculations support the site-selective substitution of Sr ions, favorably located in the intergrowths. The stabilization of the Ruddlesden-Popper phase and intergrowths via Sr substitution can be explained by the ionic-radius difference between Ca and Sr ions. The study reveals detailed defect structures originating from the layered perovskite structure of Ca$_{2.46}$Sr$_{0.54}$Ti$_2$O$_7$, and shows the usefulness of elemental mapping in probing the substitution effects in oxides.
