Phonon, elastic and thermodynamic properties of L12 phase Rh3Zr under pressure from first-principles

The phonon, elastic and thermodynamic properties of L12 phase Rh3Zr have been investigated by density functional theory approach combining with quasi-harmonic approximation model. The relaxed lattice parameters of L12 phase Rh3Zr at zero pressure are in good agreement with the experiment. To judge the stability of L12 phase Rh3Zr under high pressure, the phonon band structure has been studied. The results show that L12 phase Rh3Zr possesses dynamical stability in the pressure range from 0GPa to 80GPa due to the absence of imaginary frequencies. The pressure dependences of elastic constants Cij have been analyzed. All the elastic constants of Rh3Zr in a wide pressure range (0–80GPa) meet general mechanical conditions, suggesting that L12 phase Rh3Zr is mechanically stable under pressure up to 80GPa. L12 phase Rh3Zr exhibits ductility under high pressure and the pressure can improve the ductility from the results of the value of B∕G and Poisson’s ratio ν. Hence, it is obvious that the mechanical properties of Rh3Zr can be improved under high pressure. Moreover, we have obtained the thermodynamic properties using the quasi-harmonic Debye model. We note that the effect of the temperature on the Debye temperature ΘD is smaller than that of the pressure. We believe that our result will be a good guidance to future works and applications.