STRUCTURE DETERMINATION OF METAL-CERAMIC INTERFACES BY NUMERICAL CONTRAST EVALUATION OF HRTEM MICROGRAPHS

Iterative digital image matching (IDIM) between high-resolution electron micrographs and simulated images is presented as a suitable technique of structure refinement of crystal defects. Demonstrated on an MBE-grown interface between niobium and sapphire, results on the translation vector between the half-crystals of niobium and sapphire as well as on the monolayer relaxation at the boundary are obtained. The key features of the procedure are: (i) high-precision image simulation which is performed by refining the imaging conditions by IDIM using bulk-structural units near the boundary, (ii) multiple calculation of image agreement factors in parallel, and (iii) refinement of parameterized model structures by scanning the parameter space.