First-principles study of the structural, vibrational, phonon and thermodynamic properties of transition metal carbides TMC (, Zr and Hf)

The structural, vibrational, phonon and thermodynamic properties of TiC, ZrC and HfC have been investigated by first-principles calculations using the plane-wave pseudopotential method. The NaCl-type FCC structures are optimized and confirmed to be dynamically stable for these compounds. The vibrational modes at the Γ point are analyzed using group theory for the studied carbides. The lattice dynamical results regarding the phonon dispersion curves, phonon density of states and thermodynamic properties are reported within the framework of density functional perturbation theory. It is shown that these compounds exhibit similar but slightly different behaviors for the phonon related properties, which is expected because the transition metal atoms are in the same IV b group. The present calculation results compare satisfactorily to experimental and existing literature results.