Formation of stacking faults from misfit dislocations at the BaTiO3/SrTiO3 interface simulated by molecular dynamics

For advanced electronic devices the deposition of defect free of BaTiO3 thin films on SrTiO3 (0 0 1) substrates is required. The critical thickness, at which the growth mechanism changes from epitaxial growth without defects into pseudomorphic growth by introducing misfit dislocations, has been estimated in a previous study to be about four monolayers. Molecular dynamics simulations were performed in order to clarify the formation mechanism of these misfit dislocations. After the misfit dislocations have formed, they dissociate into a (1 0 1)-stacking fault and one partial dislocation migrates to the interface. The interface energy is lowered in spite of the stacking fault formation. The atomistic structure of the stacking fault on the (1 0 1) plane consists of one oxygen layer in the center and in the next layer Ba- and Ti-atoms facing each other, which is consistent with high-resolution transmission (HRTEM) observations.