Annular dark-field image simulation of the YBa2Cu3O7−δ/BaF2 interface

Scanning transmission electron microscope (STEM) images of the interface of a YBa2Cu3O7−δ (YBCO)/BaF2 thin film bilayer show a relatively wide (≈40 Å) contrasting band at the interface when viewed edge-on. Simulation of annular dark-field (ADF) images of this interface reveal that a significant contribution to this wide band of contrast is due to strain from dislocations oriented perpendicular to the incident beam direction and this contrast cannot be explained using solely a Z-contrast interpretation of ADF images. We believe that these are the first such calculations which predict that the presence of a misfit dislocation network can contribute a significant amount of contrast to cross-section ADF images of an interface.