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

• Atomically sharp BaTiO3/SrTiO3(001) interfaces (IF) studied from the first principles.
• Influence of IF stoichiometry on its electronic structure is studied.
• Depending on IF morphology significant shifts of band edges are predicted.
• Electronic charge redistribution is reported and discussed.

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.