Order of a Sort

摘要

In amorphous solids and liquids, there is no long-range translational or rotational ordering of the atoms, whereas in crystalline materials, the positions of all the atoms can be ascertained by symmetry from knowing the positions of only a few of them. In between these extremes are glassy materials, which have short- and medium-range order that spans from nearest neighbors to about 100 nm. The nature of this orderina has been a mystery and is very hard to probe experimentally, because any interference peaks that might be generated from a small volume are smeared out under normal diffraction conditions.