Ab initio investigation of surface phonons on the (0Â 0Â 1) surface of ZrC

We presented an ab initio pseudopotential study within the generalized gradient density functional approximation of the structural and electronic properties of the ZrC(0 0 1) surface. The calculated structural parameters for the ZrC(0 0 1) surface accord very well with previous experimental findings. The ZrC(0 0 1) surface is metallic, because at least one surface state crosses the Fermi level in the gap region of the projected electronic spectrum. Using our atomic and electronic structures, surface phonon dispersion curves are calculated by employing a linear response approach on the density functional perturbation theory. The calculated phonon spectrum compares very well with the experimental data. The atomic displacement patterns of the zone-center and zone-edge phonon modes are presented and analyzed for the ZrC(0 0 1) surface, carefully. Using this analyzation, energy locations and polarization characteristics of Love, Wallis, Lucas, and Fuchs-Kliewer modes have been determined.