Diffraction as a Probe of Local Atomic Structure in Functional Materials
Branton J. Campbell
Department of Physics & Astronomy
The elastic scattering of probe particles/waves (e.g. electrons, x-rays, neutrons) from an object is called diffraction, which has proved to be a powerful tool for determining the spatial arrangement of atoms in a material. For crystalline materials, constructive interference only occurs when reflecting off of certain planes of atoms at specific angles, so that the diffraction pattern consists of highly-directed “beams” of radiation. But when a crystal has defects, part of the diffracted intensity is transferred from these discrete beams into a diffuse but structured pattern. Because the useful properties of functional materials are often controlled via crystal defects, there is a pressing need to characterize the local atomic structure of a defect via the analysis and interpretation of diffuse scattering patterns. After an introductory explanation of common diffraction experiments and their applications, I will show a variety interesting diffuse scattering patterns and explain the defect-structure information that we have extracted from them.