STRUCTURAL, ELASTIC, AND HIGH-PRESSURE PROPERTIES OF CUBIC TIC, TIN, AND TIO

We have studied the structural and elastic properties of TiC, TiN, and TiO by means of accurate first principles total-energy calculations u sing the full potential linear muffin-tin orbital method. The calculat ions are based on the density functional theory and we have used the l ocal-density Hedin-Lundqvist parametrization as well as the generalize d gradient approximation proposed by Perdew and Wang for the exchange and correlation potential. The calculated values for the equilibrium v olume, bulk modulus, and elastic constants are generally in very good agreement with experiments. At elevated pressures all these compounds are predicted to undergo a structural phase transition from the relati vely open NaCl structure into the more dense CsCl atomic arrangement. The predicted transition pressure for TiO can be reached in modern hig h-pressure laboratories.