2. Surface structures

The two-dimensional (2D) periodic arrangement of atoms, molecules or ions on the surface of a material can a priori be studied by diffraction techniques using electrons, helium atoms, X-ray photons, neutrons, etc. as diffracting particles. The most commonly used method, however, is slow electron diffraction (LEED), which makes it relatively easy to determine the surface lattice for simple (low Miller index) or even vicinal (high Miller index) single-crystal faces, while obtaining the pattern itself requires a far more complex quantitative study.

Since the mid-1980s [8], a whole range of near-field microscopies (scanning tunnelling microscopy, atomic force microscopy, etc.) has been available for studying surface reconstructions and atomic-scale morphology. Generally speaking, surface preparation techniques and methods are beyond the scope of this article. They can...