Electronegativity Force Field for Prediction of Elastic Moduli.

Abstract

Macroscopic elastic moduli (i.e., bulk modulus and shear modulus) of covalent crystals are mainly determined by microscopic structures and stiffnesses. Herein, the microscopic bond and angle force constants of covalent crystals were parameterized from their atomic electronegativities, which is named the electronegativity force field (EFF). Based on this force field, the elastic moduli of covalent crystals can be directly obtained by molecular mechanics calculations. The calculated moduli for various covalent crystals are generally consistent with first-principles calculations, while the computational cost is reduced by several orders of magnitude, indicating the accuracy and efficiency of the EFF. Finally, we found 25 ultrahigh-modulus crystals with a bulk modulus greater than 350 GPa, which demonstrates that this force field can be used for screening of ultrahigh-modulus materials from numerous crystal candidates.