近日，南昌大学廖伟强团队研究了对映体铁电手性结构域。该研究于2025年4月29日发表在《美国化学会志》上。

具有固有手性和自发极化的手性铁电晶体最近引起了人们的极大兴趣。然而，手性拓扑结构为探索奇异功能提供了一个有前景的平台，但在对映体铁电晶体中从未发现过。研究组报道了一对对映体分子铁电体，[RFAO][ReO₄]和[SFAO][ReO₄]（RFAO/SFAO=（4R，5R/4S，5S）-4-氟-1-氮杂二环[3.2.1]辛烷）。对映体在室温下在手性极性点基团2中结晶，并在350 K下分别经历两次铁电相变，其会津符号为222F2，在463 K下为432F2。 

这种相变使它们能够显示出从高到低到关（非活动）SHG-CD状态的多步可切换二次谐波发生圆二色性（SHG-CD）效应。更重要的是，研究组在对映体中观察到了螺旋手性铁电畴。据他们所知，这是在对映体铁电晶体中首次发现手性结构域。该突破性发现为极化和手性之间的相互作用提供了新的视角，并将极大地促进对具有可切换SHG-CD和手性畴的手性铁电晶体的进一步探索，以用于下一代电子光子器件。

附：英文原文

Title: Enantiomeric Ferroelectric Chiral Domains

Author: Xian-Jiang Song, Yong Ai, Xiao-Gang Chen, Yan Qin, Yuan-Yuan Tang, Hui-Peng Lv, Peng-Fei Li, Hang Peng, Yan-Ran Weng, Huan-Huan Chen, Ren-Gen Xiong, Wei-Qiang Liao

Issue&Volume: April 29, 2025

Abstract: Chiral ferroelectric crystals with inherent chirality and spontaneous polarization have recently gained considerable interest. However, the chiral topological texture, which provides a promising platform for exploring exotic functionalities, has never been found in enantiomeric ferroelectric crystals. Here, we report a pair of enantiomeric molecular ferroelectrics, [RFAO][ReO4] and [SFAO][ReO4] (RFAO/SFAO = (4R,5R/4S,5S)-4-fluoro-1-azabicyclo[3.2.1]octane). The enantiomers crystallize in the chiral-polar point group 2 at room temperature and undergo two ferroelectric phase transitions with an Aizu notation of 222F2 at 350 K and 432F2 at 463 K, respectively. Such phase transitions enable them to show a multistep switchable second-harmonic generation circular dichroism (SHG-CD) effect from high to low to off (inactive) SHG-CD states. More importantly, we observed spiral chiral ferroelectric domains in the enantiomers. To the best of our knowledge, this is the first discovery of chiral domains in enantiomeric ferroelectric crystals. Our breakthrough findings give new sights into the interplay between polarization and chirality and will greatly stimulate further exploration of chiral ferroelectric crystals with switchable SHG-CD and chiral domains for next-generation electronic-photonic devices.

DOI: 10.1021/jacs.5c04038

Source: https://pubs.acs.org/doi/abs/10.1021/jacs.5c04038