Ferroelectric phase transitions in na-ca-halide perovskites

Abstract

We have examined the possibility of structural phase transitions in the NaCaX₃ compounds, where X is F, Cl, Br or I, using both lattice statics and molecular dynamics techniques. We find the structures of these materials to be distorted perovskites at room temperature. We predict that each of these compounds should become ferroelectric, with the fluoride having the highest polarization (21μC/cm² at room temperature).