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

Abstract

A new one-dimensional (1D) organic–inorganic hybrid ferroelectric connected by corner-shared anionic square pyramids was 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, second-harmonic generation signal reaches about 0.82 relative to KH₂PO₄ (KDP), and ferroelectric loop reveals a polarization of about 0.30 µC cm^–2. This findings indicate the first observation of 1D hybrid ferroelectric exhibiting lone pair stereoactivity based on square pyramids, providing a new way for exploring more advanced ferroelectrics.