First-principles study of optical, elastic anisotropic and thermodynamic properties of TiN under high temperature and high pressure

摘要

The optical, elastic anisotropic and thermodynamic properties of TiN in theNaCl (B1) structure are analyzed in detail in the temperature range from 0 to2000 K and the pressure range from 0 to 20 GPa. From the calculated dielectricconstants, a first order isostructural phase transition between 29 and 30 GPais found for TiN. The absorption spectra exhibit high values ranging from thefar infrared region to the ultra-violet one. The anisotropy value of Young'smodulus of TiN is smaller than that of c-BN at 0 GPa and the anisotropy of TiNclearly increases with an increase of pressure. The effects of pressure andtemperature on the bulk modulus, Gr\"uneisen parameter, Gibbs free energy, andDebye temperature are significant. The Gr\"uneisen parameter of TiN is muchlarger than that of c-BN. At temperatures below 1000 K, TiN's heat capacity ismuch larger than that of c-BN.