<i>Ab initio</i> study of the low‐pressure phases of TiO

Abstract

Abstract A careful and detailed ab initio study of the structural properties and electronic band structures of some interesting crystal phases of Ti O is presented in this work. Experimentally, at 460 K, Ti O adopts the monoclinic phase, with space group C2/m, and exhibits semiconducting properties. After heating to approximately 514 K, this compound adopts the orthorhombic phase, space group Cmcm, and exhibits metallic behavior. To determine the ground state of Ti O , density functional theory (DFT) with the local spin density approximation (LSDA) approach is used. The LSDA method is to take into account the highly correlated characteristics of the Ti O system. The total energy as a function of volume is calculated for the and Cmcm crystal phases of Ti O . Additionally, the structural parameters, , and , and the transition phase induced by applying hydrostatic pressure to this compound are studied using the Birch–Murnaghan equation of state and the calculated Gibbs free energy of the system. It was determined that the phase is the most stable phase at ambient pressure and that it is not possible to predict a transition phase induced by hydrostatic pressure.