Abstract:

The phase transition of TiO2 from the rutile structure to the fluorite structure under pressure was investigated by the first principles plane-wave pseudopotential density functional theory method. The thermodynamic properties of the rutile and fluorite structures for TiO2 were obtained by the quasi-harmonic Debye model. The results obtained are in good agreement with the experimental data and other theoretical results. We found that the rutile-to-fluorite transition of TiO2 occurred at 47.74 GPa from the Gibbs energy calculations. Moreover, the dependence of the relative volume (V/V0 ), the Debye temperature (Θ) and the heat capacity (CV) on the pressure (p)as well as the heat capacity (CV) on the temperature (T) were also successfully obtained.

Key words: Density functional theory, TiO2, Thermodynamic property, Phase transition, Quasi-harmonic Debye model