X-ray two-beam topography for quantitative derivation of phase shift by crystalline dislocations

Quantitative evaluation of crystalline dislocations is gaining importance in order to realize functional materials with ultimate performance. X-ray topography has been an important tool to evaluate the crystalline dislocations in bulk in a large volume, but the research up to now lacks the analysis to derive the phase at the image plane and such a situation prevents us from obtaining knowledge of lattice planes around the crystalline dislocations. Here we report a method that enables us to obtain such knowledge in a crystal using an x-ray two-beam topography at the kinematical diffraction regime. It can quantitatively derive the phase shift by the Bragg reflection around the crystalline dislocations. We observed an x-ray vortex wave field from a silicon carbide crystal containing a screw dislocation which almost perfectly agrees with simulations. This method will clarify the distribution and network of the threading screw dislocations and other dislocations in a large field of view.