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Structural stability and electronic properties of polar intermetallic CaZn2and SrZn2in both CeCu2-type and MgZn2-type structures have been investigated using first-principles method. The calculated equilibrium lattice parameters agree closely with the available experimental and other theoretical results. In terms of formation enthalpy, it is discovered that the present compounds with CeCu2-type structure are energetically more stable than that with MgZn2-type. They are all mechanically stable according to the criteria of elastic stability. In particular, we have investigated the pressure effect on the compressive behaviour and structural stability of each compound. Subsequently, the bulk modulus, shear modulus, Young’s modulus, theoretical hardness, Poisson’s ratio and Debye temperature in the ground state can be estimated using Voigt–Reuss–Hill homogenization method. Mechanical anisotropy is characterized by the anisotropic factors and direction-dependent Young’s modulus. Finally, the electronic structures are determined to reveal the bonding characteristics of considered phases. [ABSTRACT FROM PUBLISHER]

Using first principles total energy calculations within the generalized gradient approximation (GGA), we have investigated the mechanical and thermodynamics properties of C 14-type Laves phases AMg 2 (A = Ca, Sr and Ba). Our results of equilibrium lattice parameters and formation enthalpy agree closely with previous experimental results. In particular we have discussed the thermodynamic stabilities and mechanical anisotropies of these phase structures. The polycrystalline elastic moduli have been deduced by Voigt–Reuss–Hill arithmetic approximation. Subsequently, the ductility and brittleness are characterized with the estimation from Pugh’s rule ( B / G ) and Poisson’s ratio. Additionally, the Debye temperature is calculated from the average elastic wave velocity obtained from bulk and shear moduli. The calculations of density of states and charge density difference are performed to reveal the underlying mechanism of electronic structure. Finally, variations of thermodynamic properties with temperature are predicted by calculating phonon frequencies combined within the quasi-harmonic approximation. [ABSTRACT FROM AUTHOR]