Structural stability of β-TiO with disordered vacancies: A first-principles calculation

The structural stability of β-TiO with FCC NaCl structure was investigated via the first-principles method based on density functional theory. It found that the β-TiO with certain content vacancies was the most stable structure determined by calculation using GGA density functional with the continuously increasing vacancies. The electronic properties of β-TiO such as DOS, PDOS, bond population and charge density, were also calculated which demonstrated that Ti–Ti bond forms around O-vacancy due to the weaker O–Ti bond. The calculating results about thermodynamic and elastics properties are given and compared with the actual β-TiO. Based on the above calculation results, the relaxation structure of β-TiO with vacancies is found to be consistent with the actual structures having a disordered array of stoichiometric vacancies about 15% at both oxygen and titanium sites. All of these validate the advantages of our investigations with GGA method for predicting physical properties in β-TiO.