When BaTiO3 thin films were deposited onto SrTiO3 (001) substrates at approximately 700C, epitaxial growth without defects first occurred but, at a critical thickness, it changed to pseudomorphic growth; with the introduction of misfit dislocations. Cross-sectional high-resolution transmission electron microscopy showed that these dislocations were located at the interface. Stacking faults on (101) planes were also observed. Molecular dynamics simulations were used to elucidate the formation of the dislocations. The critical thickness for the appearance of misfit dislocations was found to be approximately 4 monolayers. This limit increased slightly with temperature. The misfit dislocations dissociated into partial dislocations, and migrated to the interface by forming stacking faults on (101) planes.

Molecular Dynamics Calculations of Misfit Dislocations at the BaTiO3/SrTiO3 Interface. W.Wunderlich, M.Fujimoto, H.Ohsato: Thin Solid Films, 2000, 375[1-2], 9-14