Unraveling the Suppression of Oxygen Octahedra Rotations in A_{3}B_{2}O_{7} Ruddlesden-Popper Compounds: Engineering Multiferroicity and Beyond.
Unraveling the Suppression of Oxygen Octahedra Rotations in A_{3}B_{2}O_{7} Ruddlesden-Popper Compounds: Engineering Multiferroicity and Beyond.
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DOI：
10.1103/physrevlett.125.157601
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发表时间：
2020-10
影响因子：
8.6
通讯作者：
Yajun Zhang;Jie Wang;Philippe Ghosez
中科院分区：
文献类型：
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作者：
Yajun Zhang;Jie Wang;Philippe Ghosez
极性畸变和BO_{6}八面体旋转之间的竞争是解释各种ABO_{3}钙钛矿基态的关键。在这里，我们从第一性原理计算表明，层间褶皱和旋转之间的类似竞争在层状Ruddlesden-Popper（RP）钙钛矿中起着关键作用。这种竞争解释了在岩盐层中稀土离子对A3 B 2 O 7}化合物中氧八面体旋转和杂化反常铁电性的抑制，同时也与RP系统中的负热膨胀和维数决定的带隙等现象有关。此外，我们强调RP钙钛矿在控制这种竞争方面比ABO_{3}钙钛矿提供了更大的灵活性，并提出了四种不同的策略来调节这种竞争，这些策略被证明是有希望设计新的多铁性材料的。它们是通用的，也可以用于调整负热膨胀和带隙。
The competition between polar distortions and BO_{6} octahedra rotations is well known to be critical in explaining the ground state of various ABO_{3} perovskites. Here, we show from first-principles calculations that a similar competition between interlayer rumpling and rotations is playing a key role in layered Ruddlesden-Popper (RP) perovskites. This competition explains the suppression of oxygen octahedra rotations and hybrid improper ferroelectricity in A_{3}B_{2}O_{7} compounds with rare-earth ions in the rocksalt layer and also appears relevant to other phenomena like negative thermal expansion and the dimensionality determined band gap in RP systems. Moreover, we highlight that RP perovskites offer more flexibility than ABO_{3} perovskites in controlling such a competition and four distinct strategies are proposed to tune it. These strategies are shown to be promising for designing new multiferroics. They are generic and might also be exploited for tuning negative thermal expansion and band gap.