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 (T_t), which is promising for a variety of applications. Quantitative prediction of T_t is essential but lacking. Herein we propose a concept of averaged effective electronegativity (AEE) and establish a linear relationship between the T_t 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 Sc_x1Zr_x2Hf_x3Fe_x4Mo_y1V_y2O₁₂ and a NTE compound Zr₂MoVPO₁₂ with expected T_t. 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 T_t.