Experimental and calculated images of planar defects at high resolution

Abstract

Calculations of the contrast in n-beam images of isolated edge-on crystallo-graphic shear planes (CSP) have been carried out. The multi-slice method in combination with periodic continuation was used, thereby overcoming the resolution limitations inherent in the column approximation. The effects of crystal thickness, crystal tilt, CSP shear vector, defoeus, spherical aberration and objective aperture have been investigated and the results confirmed by comparison with experimental focal-series images. The applicability of the projected-charge-density approximation for the intuitive interpretation of image contrast at a resolution of about 4 Å has been demonstrated for both (132) and (210) CSPs in rutile. The latter provide examples of metal-rich and metal-deficient faults, respectively.