Role of structural vacancies in the stabilization of the basic B1 structure in nonstoichiometric titanium monoxide TiO y

Abstract

The electron structures and formation enthalpies of vacancy-free cubic TiO, vacancy-ordered monoclinic Ti5O5, and vacancy-disordered cubic TiO y have been investigated using DFT+GGA calculations. Ti5O5 was found to be the stablest phase and TiO was found to be the least stable. The reason for the stability of the titanium and oxygen vacancies in the basic B1 structures of Ti5O5 and TiO y has been deduced. The titanium vacancies lead to a decrease in the Fermi energy. Oxygen vacancies cause strengthening in covalent Ti-Ti bonding. © 2013 Allerton Press, Inc.