Abstract:
Using a first-principles pseudopotential technique, we have presented static and dynamical properties of cubic-BN. The calculated values for the lattice constant, bulk modulus, its first derivative and optical dielectric constant are in good agreement with available experimental and theoretical results. Phonon dispersion curves and density of states for cubic-BN were calculated by employing a density functional perturbation theory. In particular, the calculated zone-center and zone-edge phonons compare very well with available experimental results. The calculated structural parameters for the BN(110) surface are in good agreement with previous theoretical results. The highest surface optical phonon mode resonates with the bulk continuum along Gamma - X' (i.e. across the top-layer B-N atomic chain). Along other symmetry directions, this mode lies above the bulk continuum. The surface acoustic branches lie below the bulk continuum. Energy locations and polarization characteristics of surface rotational and bond stretching phonon modes have been determined. (c) 2005 Elsevier B.V. All rights reserved.