Column Approximation and Howie–Whelan’s Method for Dynamical Electron Diffraction—Theory for Observation of Lattice Defects

In Chap. 26 , weColumn approximation study Bethe’sHowie-Whelan’s method methodAttice defects by which the wave field at the exit surface of a crystal is calculated by solving Schrodinger equationSchrodinger equation with help of the Bloch theoremBloch theorem. How can we calculate the wave field after a crystal including dislocationsDislocations and planar defectsPlanar defects? For interpretation of electron microscope images of the defects, we need calculation of exit wave field as a function of real space coordinatesReal space coordinates (x, y), not in reciprocal spaceReciprocal space (u, \(\upsilon\) ). The present “column approximation method” was developed to connect “description in real space” and “dynamical diffraction effects ordinarily described in reciprocal space.”