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Abstract: The electronic, elastic and mechanical properties of eight binary B 2 – type intermetallic compounds of Ag and Au (AgX and AuX, X=Mg, Sc, Zn and Cd) have been studied systematically using first principles density functional theory within generalized gradient approximation. Ground state properties such as lattice constant (a 0), bulk modulus (B), its pressure derivative (B′) and elastic constants are calculated. The present results are in good agreement with the experimental and other available theoretical results. Poisson’s ratio (σ), Young’s moduli (E), shear moduli (GH ) and the ratio of elastic anisotropy factor (A) are also estimated. Ductility for these compounds is further analysed by calculating the ratio of B/GH and Cauchy pressure (C 12–C 44). Amongst all the intermetallics AuZn is found to be most ductile due to the presence of strong metallic bonding, and AgZn is least ductile in all the Au and Ag intermetallic compounds. [Copyright &y& Elsevier]

Abstract: To investigate the structural, elastic, and lattice dynamical properties of the germanium diiodide, we have performed the first-principles calculations by using the local density approximation method based on density-functional theory. Some basic physical parameters such as lattice constant, bulk modulus and its first derivatives, elastic constants, shear modulus, Young’s modulus, and Poisson’s ratio are calculated. The phonon dispersion curves, electronic band-structures, and total and partial density of states have also been calculated for ground state C6 phase of GeI2. Our results show that this structure has got 1.72eV direct band gap. Our secondary results on the temperature-dependent behavior of thermodynamical properties such as entropy, heat capacity, internal energy, and free energy are also presented for the same compounds. The obtained results are in good agreement with the available experimental and other theoretical data. [ABSTRACT FROM AUTHOR]