Pressure-dependent mechanical and thermodynamic properties of newly discovered cubic Na2He

Recently for the first time, a stable compound of He and Na (Na2He) is predicted at high pressure. We explore the pressure-dependent elastic, mechanical and thermodynamic properties of this newly discovered Na2He by using ab initio technique. The calculation presents good accordance between the theoretical and experimental lattice parameters. Though the most stable structure of Na2He is found at 300 GPa, present study ensures the mechanical stability of this compound up to 500 GPa. The study of Cauchy pressure, Pugh's ratio, and Poisson's ratio implies the ductile manner of Na2He up to 500 GPa. According to the value of Poisson's ratio the bonding force exists in Na2He is central. The study of Zener anisotropy factor indicates that Na2He is an anisotropic material but near at 300 GPa approximately isotropic nature of Na2He is revealed. The study of the bulk modulus, shear modulus, Young's modulus and Vickers hardness implies that the hardness of Na2He can be improved by applying external pressure. However, the Debye temperature, melting temperature and minimum thermal conductivity of Na2He are also calculated and discussed at different pressures.