Anisotropic Elastic, Electronic and Vibrational Properties of the Semiconductor AgScX (X = Ge, C) Compounds

The structural, mechanic anisotropy, electronic and dynamic properties of AgScX (X=Ge, C) which are half-Heusler compounds were analyzed by first-principles calculations. The obtained stable equilibrium lattice parameters in the MgAgAs structure are 6.304 angstrom for AgScGe and 5.591 angstrom for AgScC, and it is compatible with theoretical values. Mechanical parameters such as shear modulus, Young's modulus, Poisson's ratio, G/B ratio, Cauchy pressure, hardness and anisotropy factors, and the mechanical stability have been calculated including three elastic constants. The elastic anisotropy of AgScX (X=Ge, C) compounds has been investigated in terms of Poisson's ratio, linear compressibility, shear modulus, and Young's modulus. Furthermore, the calculated electronic band structures revealed that AgScX (X=Ge, C) compounds have an indirect gap in the Gamma-K Brillouin zone. The phonon dispersion curves have also been plotted with corresponding phonon density of states. It is considered that all the compounds are dynamically stable in the C1b structure.