Ferroelectricity in the Dion-Jacobson CsBiNb$_2$O$_7$ from first principles

TL;DR

This study uses first-principles calculations and group theory to investigate ferroelectricity in CsBiNb$_2$O$_7$, predicting significant polarization and suggesting experimental validation.

Contribution

First-principles analysis combined with group theory to identify ferroelectricity in CsBiNb$_2$O$_7$ and estimate its polarization.

Findings

CsBiNb$_2$O$_7$ is ferroelectric with P$_s$=40μC/cm$^2$

Energy surface analysis supports ferroelectric phase stability

Proposes experimental studies for confirmation

Abstract

We have studied ferroelectricity in Dion-Jacobson CsBiNb$_2$O$_7$ 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 CsBiNb$_2$O$_7$ is a ferroelectric with a polarization of P$_s$=40$\mu$C cm$^{-2}$. We propose further experiments to clarify this point.