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标题：Organic enantiomeric high-Tc ferroelectrics
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作者：Peng-Fei Li ; Wei-Qiang Liao ; Yuan-Yuan Tang 等
期刊名称：Proceedings of the National Academy of Sciences
印刷版ISSN：0027-8424
电子版ISSN：1091-6490
出版年度：2019
卷号：116
期号：13
页码：5878-5885
DOI：10.1073/pnas.1817866116
出版社：The National Academy of Sciences of the United States of America
摘要：For nearly 100 y, homochiral ferroelectrics were basically multicomponent simple organic amine salts and metal coordination compounds. Single-component homochiral organic ferroelectric crystals with high-Curie temperature ( T c) phase transition were very rarely reported, although the first ferroelectric Rochelle salt discovered in 1920 is a homochiral metal coordination compound. Here, we report a pair of single-component organic enantiomorphic ferroelectrics, ( R )-3-quinuclidinol and ( S )-3-quinuclidinol, as well as the racemic mixture ( Rac )-3-quinuclidinol. The homochiral ( R )- and ( S )-3-quinuclidinol crystallize in the enantiomorphic-polar point group 6 ( C 6) at room temperature, showing mirror-image relationships in vibrational circular dichroism spectra and crystal structure. Both enantiomers exhibit 622 F 6-type ferroelectric phase transition with as high as 400 K [above that of BaTiO3 ( T c = 381 K)], showing very similar ferroelectricity and related properties, including sharp step-like dielectric anomaly from 5 to 17, high saturation polarization (7 μC/cm2), low coercive field (15 kV/cm), and identical ferroelectric domains. Their racemic mixture ( Rac )-3-quinuclidinol, however, adopts a centrosymmetric point group 2/ m ( C 2h), undergoing a nonferroelectric high-temperature phase transition. This finding reveals the enormous benefits of homochirality in designing high- T c ferroelectrics, and sheds light on exploring homochiral ferroelectrics with great application.
关键词：ferroelectricity ; homochirality ; enantiomer ; ferroelectric domains