Structural, elastic and mechanical properties of orthorhombic SrHfO _3 under pressure from first-principles calculations

摘要

Structural, elastic and mechanical properties of orthorhombic SrHfO _3 under pressure have been investigated using the plane-wave ultrasoft pseudopotential technique based on the first-principles density functional theory. The calculated equilibrium lattice parameters and elastic constants of orthorhombic SrHfO _3 at zero pressure are in good agreement with the available experimental and calculational values. The lattice parameters, total enthalpy, elastic constants and mechanical stability of orthorhombic SrHfO _3 as a function of pressure were studied. With the increasing pressure, the lattice parameters and volume of orthorhombic SrHfO _3 decrease whereas the total enthalpy increases. Orthorhombic SrHfO _3 is mechanically stable with low pressure (<52.9 GPa) whereas that is mechanically instable with high pressure (>52.9 GPa). The bulk modulus, shear modulus, Youngs modulus and mechanical anisotropy of orthorhombic SrHfO _3 as a function of pressure were analyzed. It is found that orthorhombic SrHfO _3 under pressure has larger bulk modulus, better ductility and less mechanical anisotropy than orthorhombic SrHfO _3 at 0 GPa.