Elastic anisotropy and thermodynamics properties of BiCu2PO6, BiZn2PO6 and BiPb2PO6 ceramics materials from first-principles calculations

Abstract

In present work, the elastic properties, anisotropy in elasticity and thermodynamics properties for BiCu2PO6, BiZn2PO6 and BiPb2PO6 ceramics materials were investigated using the first-principles calculation. The formation enthalpy and phonon frequencies confirm that three BiX2PO6 (X = Cu, Zn, and Pb) compounds exhibit the structural stability. The calculated elastic constants and elastic moduli indicate that BiZn2PO6 has the better mechanical properties than BiCu2PO6 and BiPb2PO6 at ground state. The values of B/G confirm that three BiX2PO6 compounds all exhibits the ductile behavior. The values of anisotropic parameters, three-dimensional surface constrctions and two-dimensional projection curves of the Young's modulus reveal the anisotropic degree of three BiX2PO6 compounds. The thermodyanmic parameters indicate that three BiMn2XO6 materials show the thermal stability from 0 to 1000 K. The obtained physical parameters can provide the useful data for the further experimental investigations.