A linear scaling law for predicting phase transition temperature via averaged effective electronegativity derived from A2M3O12-based compounds.

Abstract

The chemical flexibility of A2M3O12-based compounds enables the design of materials with versatile functionalities such as ferroelastic switching, ion conduction and negative thermal expansion (NTE) above the ferroelastic transition temperature (Tt), which is promising for a variety of applications. Quantitative prediction of Tt is essential but lacking. Herein we propose a concept of averaged effective electronegativity (AEE) and establish a linear relationship between the Tt and AEE for A2M3O12-based compounds. The linear scaling law is validated using first principles calculations of the effective charge on oxygen and its effectiveness is verified experimentally by designing high entropy compounds Scx1Zrx2Hfx3Fex4Moy1Vy2O12 and a NTE compound Zr2MoVPO12 with expected Tt. Generalization of the linear scaling law to other NTE oxides with displacive phase transition is also demonstrated. The findings can be used as a simple and effective approach to guide the design of novel compounds with desired properties and Tt.