Ab initio calculation of mechanical and thermodynamic properties of Gd2Zr2O7 pyrochlore

Abstract

Using density functional theory with GGA + U method, the mechanical, thermodynamic properties and minimum thermal conductivity of Gd2Zr2O7 pyrochlore are investigated. The obtained lattice parameters and density with GGA + U method are consistent with other experimental and theoretical results. The calculated elastic constants reveal that Gd2Zr2O7 pyrochlore is mechanically stable and ductile material under high pressure. From the direction dependence Young's modulus and Zener ratio analysis, it is shown that Gd2Zr2O7 pyrochlore is weak anisotropy at 0 GPa and 10 GPa. In addition, the pressure effect on the Young's modulus, bulk modulus, sound wave velocity, shear modulus and minimum thermal conductivity of Gd2Zr2O7 pyrochlore are analyzed. Subsequently, the thermodynamic properties such as the constant volume heat capacity, thermal expansion coefficient, Debye temperature, thermal expansion coefficient and entropy under high pressure and temperature are also estimated with the quasi-harmonic Debye model.