Structural and elastic properties of Pd–Zr compounds studied by ab initio calculation

Abstract

Over one hundred and thirty Pd–Zr intermetallic compounds, including stable and hypothetical ones, are first identified, then the corresponding physical properties such as formation enthalpies, elastic constants and bulk modulus are investigated by ab initio calculations. Based on the calculated formation enthalpies of these Pd–Zr compounds with a variety of structures and different compositions, the ground-state convex hull is derived for the Pd–Zr system. It also turns out that most of the calculated results match well with the available experimental observations. Therefore, the calculated results of stable and hypothetical phases can provide a basis for further thermodynamic calculations and atomistic simulations. Interestingly, it is found that the formation enthalpies of these compounds approximately vary linearly with the atomic volumes for Pd–Zr compounds. In addition, due to the anharmonicity of interatomic interaction, the bulk modulus of these compounds exhibit a negative linear correlation with the atomic volumes, i.e. phases with small atomic volumes usually have large bulk modulus.