Structure, energetics, and electronic properties of stacking fault defects in ilmenite-structured ZnTiO3

The stacking fault behaviors on ilmenite ZnTiO3 were investigated by calculating the generalized stacking fault (GSF) energies using density functional theory (DFT) based on first principles calculations and classical calculations employing effective partial charge interatomic potentials. The results show that stable and unstable stacking fault energies are in qualitative agreement and provide the same sequence of stacking fault energies, although there exist quantitative differences with DFT providing lower stable and unstable stacking fault energy values than those from classical potential calculations. The.-surfaces of two low energy surfaces, (1 1 0) and (1 0 4), of ZnTiO3 were fully mapped together with ideal shear stress (ISS) calculations. It was found that stacking faults along < 4 5 (1) over bar >/{1 0 4} are preferred energetically and are most probable to nucleate dislocations due to their significantly lower gamma(sf)/gamma(usf) values. The atomic structures of the low energy stacking faults were analyzed and their electronic structures calculated and compared with bulk ZnTiO3 structures. It was found that stacking fault formation led to narrowing of the band gap and creating inter-bandgap states, mainly due to the dangling bonds and bonding defects, as compared to the bulk structures.