First-principles structural, electronic and vibrational properties of zinc-blende zirconium carbide

We have systematically studied the structural, elastic, electronic, dynamical and thermodynamical properties of zirconium carbide in zinc blende (ZB) phase using ab-initio calculations based on density-functional theory. The calculated structural parameters, such as the lattice constant, bulk modulus and elastic constants, are in good agreement with available theoretical data. The calculated bulk modulus and shear modulus show that ZB-ZrC is softer than RS-ZrC. Further, the anisotropic factor, Poissonʹs ratio, and Youngʹs modulus are also calculated and discussed. ZB-ZrC is anisotropic. Electronic band structure indicates narrow bandgap semiconducting nature of ZrC in ZB phase. In the phonon dispersion curves of ZB-ZrC all phonon frequencies are positive and hence indicate that the compound is dynamically stable. Temperature variations of thermodynamical functions such as free energy, internal energy, entropy and lattice specific heat at constant volume are also calculated and discussed. The elastic and dynamical stability is independent of pseudo-potentials.