4. Glossary

Amorphous material

A solid with no ordered atomic structure at medium and long distances, its atoms are randomly distributed as in a liquid.

Polycrystal

A polycrystal or polycrystalline material is a solid material made up of a multitude of small crystals called "crystallites" of varying size, shape and orientation, separated by grain boundaries. In contrast, a monocrystal or monocrystalline material is made up of a single crystal.

Single crystal

A monocrystal or monocrystalline material consists of a single homogeneous crystal whose lattice planes have a uniform orientation throughout the volume.

Gap

Point defect corresponding to the absence of an atom or ion at a normally occupied site in a crystalline structure....