A one-dimensional hybrid ferroelectric exhibiting lone pair stereoactivity based on square pyramids

Abstract

A new one-dimensional (1D) organic–inorganic hybrid ferroelectric connected by corner-sharing anionic square pyramids is reported. Structural analyses reveal that the ordering of organic cations and lone pair stereoactivity of square pyramids play a synergistic role in the ferroelectric transition. Dielectric properties show a small peak-like and a step-like anomaly, the second-harmonic generation signal reaches about 0.82 relative to KH₂PO₄ (KDP), and the ferroelectric loop reveals a polarization of about 0.30 µC cm⁻². These findings indicate the first observation of a 1D hybrid ferroelectric exhibiting lone pair stereoactivity based on square pyramids, providing a new way for exploring more advanced ferroelectrics.