First principles hybrid DFT calculations of BaTiO3/SrTiO3(001) interface

Abstract We present a first-principles study of BaTiO₃/SrTiO₃(001) interfaces taking into account non-stoichiometric compositions. By means of hybrid exchange-correlation functional within density functional theory (DFT) we demonstrate that charge redistribution in the interface region weakly affects the electronic structure of studied material, while change in the stoichiometry (termination of deposited BaTiO₃(001) thin film) yields in significant shifts of band edges. The optical band gap of BaTiO₃/SrTiO₃(001) interface depends mostly on BaO or TiO₂ termination of the upper layer. Based on results of our calculations we predict enhancement of the Ti-O chemical bond covalency near the BaTiO₃/SrTiO₃(001) interface as compared to the BaTiO₃ bulk.