Ferroelectricity in the Dion-Jacobson CsBiNb2O7 from first principles

We have studied ferroelectricity in Dion-Jacobson CsBiNb2O7 from first principles. Using group-theoretical analysis and first-principles density functional calculations of the total energy and phonons, we perform a systematic study of the energy surface around a paraelectric prototypic phase. Our results suggest that CsBiNb2O7 is a ferroelectric with a polarization of Ps=40μCcm−2. We propose further experiments to clarify this point.