Stacking-fault contrast from phonon-scattered electrons

Analytical expressions are derived for the stacking-fault contrast from phonon-scattered electrons. Phonon scattering is taken into account to first order and the elastic scattering from the defect is considered dynamically. Stacking-fault contrast profiles are calculated in a two beam approximation and a comparison is made with the experimental results of Kamiya and Nakai (see abstr. A58444 of 1971). Methods are developed to determine the character of the fringes where the fault meets the foil surfaces. Contrary to the situation in perfect crystals, phonon scattering processes, where the wavevector normal to the foil is not conserved, play an important role in the contrast formation in crystals with defects.