Defect energetics in the SrTiO3-LaCrO3 system

Oxide interfaces have attracted a huge amount of interest in recent years due to their novel functionalities that are not possible in bulk. Here we employ atomistic simulation techniques to study the defect properties and oxygen ion migration energy in bulk SrTiO₃, LaCrO₃ and SrTiO₃–LaCrO₃ interface. The SrO and La₂O₃ “Schottky-like” defects are found to be the most favourable intrinsic defects in their respective bulk structures and also at interface layers. While defect energies calculated at interface layers are not significantly changed compared to that calculated in the bulk LaCrO₃, significant changes are noted in Schottky defects and oxygen Frenkel between bulk SrTiO₃ and the interface. The activation energies for the oxygen ion diffusion in bulk SrTiO₃ and LaCrO₃ are calculated to be 0.64 eV and 0.53 eV, respectively, suggesting that both materials will present favourable diffusion pathways. In general, there is a reduction in the activation energies of oxygen ion migration at the interface compared to bulk structures. In particular, in the Cr layer, activation energy is calculated to be 0.36 eV implying that interface plays an important role in the oxygen ion migration and therefore such an interface is of interest for use in advanced electrochemical devices.