FlächenDiffraction

FlächenDiffraction, meaning "surface diffraction" in German, refers to the phenomenon observed when waves, such as light or X-rays, interact with a two-dimensional surface or a very thin film. Unlike bulk diffraction which occurs within a three-dimensional material, FlächenDiffraction is primarily sensitive to the structure and arrangement of atoms or molecules at the surface. This technique is crucial for characterizing the atomic-scale topography, ordering, and electronic properties of surfaces.

The principles of FlächenDiffraction are rooted in the wave nature of the incident particles. When these waves encounter the ordered atoms on a surface, they are scattered. Due to constructive interference of the scattered waves at specific angles, diffraction patterns emerge. These patterns are unique to the surface structure, providing information about lattice parameters, reconstruction, and the presence of adsorbates.

Common experimental techniques employing FlächenDiffraction include Reflection High-Energy Electron Diffraction (RHEED) and Grazing Incidence X-ray Diffraction (GIXRD). RHEED uses a high-energy electron beam incident at a very shallow angle to the surface, resulting in a diffraction pattern projected onto a fluorescent screen. GIXRD utilizes X-rays at grazing incidence angles to enhance surface sensitivity, with the diffracted X-rays detected by a sensor. Both methods are non-destructive and are extensively used in materials science, condensed matter physics, and chemistry for in-situ monitoring of surface growth and modifications.