Potential Multiaxial Molecular Ferroelectricity through Chiral Cation Replacement

Molecular ferroelectrics are an important class of materials
offering
chemical versatility, low toxicity, and tunable functional properties.
A major design challenge lies in achieving multiaxial properties akin
to inorganic perovskite ferroelectrics. Here, we report a series of
new potential multiaxial molecular ferroelectrics obtained by introducing
chiral cations into a structure type known to undergo a phase transition
that raises the symmetry significantly. Three of the compounds studied
show an Aizu m3̅mFm phase
transition, resulting in 24 equiv polarization directions in the polar
phase. 1H solid-state NMR was used to study the dynamics
of the organic cation, confirming rapid rotation about the 3-fold
rotation axis of the cubic cell. This blurs the chiral center to an
X-ray probe, making the distinction between Sohncke and non-Sohncke
space group choices redundant.