Atomic displacements in the modulated structure of Bi2Sr2(Ca(1-x)Pr(x))Cu2O(8+delta) and their effect on HRTEM...

The amplitude of transverse atomic displacement wave along the direction of incident electron beam exerts a significant effect on the brightness of spots in a high-resolution transmission electron microscope (HRTEM) reverse contrast image. The bright spot is associated with the projection of the modulated atomic chain along the beam direction. In general, the spot brightness is roughly inversely proportional to the amplitude of the displacement wave in an appropriate region of defocus, specimen thickness and amplitude. Monotonic decrease in the spot brightness with increasing amplitude can be attributed to the decrease in the degree of interference between scattered electrons. A complicated domain configuration has been found by the analysis of the spot brightness modulation observed in a [0 0 1] HRTEM reverse contrast image.