Coupled Ferroelectricity and Optical Activity in Optically Active Ferroelectrics

Ferroelectricity was initially discovered in 1921 in
Rochelle salt
(potassium sodium tartrate tetrahydrate), a chiral compound containing
a chiral unit. However, the inherent relationship between coupled
ferroelectricity and optical activity in chiral ferroelectrics derived
from achiral units, as well as in polar ferroelectrics, remains insufficiently
explored. In this regard, we propose a fresh concept of optically
active ferroelectrics, specifically those crystallizing in seven optically
active point groups (1, 2, 4, 3, 6, m, mm2). Subsequently, we elucidate the mechanism of coupled ferroelectricity
and optical activity, emphasizing the cooperative interplay of chirality
and polarity flipping under the influence of an electric field. Finally,
we expound on the applications of this principle for the in
situ generation of chiral enantiomers and polar isomers,
thereby providing valuable insights into the chiral/polar research
community and advancing our comprehension of ferroelectricity.