Observation of Ferrochiral Transition Induced by an Antiferroaxial Ordering of Antipolar Structural Units in Ba(TiO)Cu4(PO4)4
Observation of Ferrochiral Transition Induced by an Antiferroaxial Ordering of Antipolar Structural Units in Ba(TiO)Cu4(PO4)4
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Ba(TiO)Cu4(PO4)4 中反极性结构单元的反铁轴有序诱导的铁手性转变的观察
DOI：
10.1021/jacs.1c00391
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发表时间：
2021
影响因子：
15
通讯作者：
Kimura Tsuyoshi
中科院分区：
文献类型：
--
作者：
Hayashida Takeshi;Kimura Kenta;Urushihara Daisuke;Asaka Toru;Kimura Tsuyoshi
手性铁跃迁，即涉及手性的跃迁，提供了一个独特的机会来实现手性的非挥发性可逆控制与外场。然而，表现出纯手性铁跃迁的材料，不伴有其他类型的铁跃迁，是非常罕见的。在本研究中，我们提出了纯铁手性转变是通过结构单元的反极性和反铁轴顺序的结合来实现的，并通过对手性化合物Ba(TiO)Cu4(PO4)4的研究证实了这一提议。单晶x射线衍射测量表明，该材料经历了二级手性铁跃迁，其序参数由反铁轴（交错）旋转的反极性结构单元描述，从而证明了我们的建议。此外，通过测量旋光性的空间分布，我们成功地可视化了铁手性域在转变温度下的温度演变，并证明了手性与旋光性之间的关系。这项工作为寻找纯铁手性过渡提供了指导，从而为实现手性的铁性控制提供了机会。
Ferrochiral transition, i.e., a transition involving an emergence of chirality, provides an unique opportunity to achieve a nonvolatile reversible control of chirality with external fields. However, materials showing pure ferrochiral transitions, which are accompanied by no other types of ferroic transition, are exceedingly rare. In this study, we propose that a pure ferrochiral transition is achieved by a combination of antipolar and antiferroaxial orderings of structural units, and substantiate this proposal through a study of the chiral compound Ba(TiO)Cu4(PO4)4. Single crystal X-ray diffraction measurements have revealed that this material undergoes a second order ferrochiral transition whose order parameter is described by an antiferroaxial (staggered) rotation of antipolar structural units, thus demonstrating our proposal. Furthermore, by measuring spatial distributions of optical rotation, we successfully visualized a temperature evolution of ferrochiral domains across the transition temperature and demonstrated the relationship between chirality and optical rotation. This work provides a guide to find a pure ferrochiral transition, thus providing an opportunity to achieve a ferroic control of chirality.