论文标题
srbi $ _2 $（ta，nb）$ _ 2 $ o $ $ _9 $的铁电开关途径和域结构
Ferroelectric Switching Pathways and Domain Structure of SrBi$_2$(Ta,Nb)$_2$O$_9$ from First Principles
论文作者
论文摘要
几个分层的钙钛矿氧化物铁电去的家族在极化和结构阶参数（例如八面体旋转失真）之间表现出耦合。这种耦合为新型电场对材料特性的操纵提供了机会，还可以稳定复杂的域模式和域壁涡流。在带有这种耦合订单的分层钙壶中，Aurivillius-phase氧化物srbi $ _2b_2 $ o $ _9 $（$ b $ = ta，nb）以其出色的室温室温铁皮性能而闻名。这项工作将小组理论分析与密度功能理论计算结合在一起，以检查SRBI $ _2B_2 $ o $ $ _9 $的铁电交换过程。鉴定出低能的两步铁电开关路径，偏振反转通过结构阶参数旋转促进。对域结构的分析揭示了耦合顺序参数的相对能量如何转化为由域壁涡流结构链接的几种不同域壁类型的网络。对Srbi $ _2b_2 $ o $ _9 $的铁电开关和域结构的比较与分层$ n $ = 2 ruddlesdledlesden-popper Hybrid Hybrid不当铁电气的结构进行了比较。该结果为如何通过工程化极光氧化物的复杂晶体结构来优化铁电特性提供了新的见解。
Several families of layered perovskite oxide ferroelectrics exhibit a coupling between polarization and structural order parameters, such as octahedral rotation distortions. This coupling provides opportunities for novel electric field-based manipulation of material properties, and also stabilizes complex domain patterns and domain wall vortices. Amongst layered perovskites with such coupled orders, the Aurivillius-phase oxides SrBi$_2B_2$O$_9$ ($B$=Ta, Nb) are well-known for their excellent room temperature ferroelectric performance. This work combines group theoretic analysis with density functional theory calculations to examine the ferroelectric switching processes of SrBi$_2B_2$O$_9$. Low-energy two-step ferroelectric switching paths are identified, with polarization reversal facilitated by structural order parameter rotations. Analysis of the domain structure reveals how the relative energetics of the coupled order parameters translates into a network of several distinct domain wall types linked by domain wall vortex structures. Comparisons are made between the ferroelectric switching and domain structure of SrBi$_2B_2$O$_9$ and those of the layered $n$=2 Ruddlesden-Popper hybrid improper ferroelectrics. The results provide new insight into how ferroelectric properties may be optimized by engineering the complex crystal structures of Aurivllius-phase oxides.
