Ferroelectricity in corundum derivatives

TL;DR

This paper investigates the ferroelectric reversal mechanisms in corundum derivative materials, categorizes their potential for ferroelectricity, and predicts new ferroelectric candidates using first-principles calculations.

Contribution

It introduces a method to study ferroelectric reversal paths in corundum derivatives and identifies conditions for ferroelectricity and magnetic compatibility.

Findings

Only two of four corundum classes allow ferroelectric reversal.

Empirical measures can estimate energy barriers for FE reversal.

Predicted several new potential ferroelectric materials.

Abstract

The search for new ferroelectric (FE) materials holds promise for broadening our understanding of FE mechanisms and extending the range of application of FE materials. Here we investigate a class of ABO3 and A2BB'O6 materials that can be derived from the X2O3 corundum structure by mixing two or three ordered cations on the X site. Most such corundum derivatives have a polar structure, but it is unclear whether the polarization is reversible, which is a requirement for a FE material. In this paper, we propose a method to study the FE reversal path of materials in the corundum derivative family. We first categorize the corundum derivatives into four classes and show that only two of these allow for the possibility of FE reversal. We then calculate the energy profile and energy barrier of the FE reversal path using first-principles density functional methods with a structural constraint. Furthermore, we identify several empirical measures that can provide a rule of thumb for estimating the energy barriers. Finally, the conditions under which the magnetic ordering is compatible with ferroelectricity are determined. These results lead us to predict several potentially new FE materials.