Superstructure (condensed matter)

In solid state physics, a superstructure is some additional structure that is superimposed on a higher symmetry crystalline structure.

In crystallography and group theory, a superstructure refers to a crystal structure that can be derived from another basic crystal structure under certain conditions. The concept of a superstructure is related to but not the same as the concept of a superlattice. However, a superlattice is a distinct concept. A superlattice is derived from the addition of nodes to a lattice resulting in a crystal structure with extended periodicity and a larger unit cell relative to the original lattice. The two terms are often incorrectly used interchangeably.

A typical and important example is ferromagnetic ordering.

In a wider sense, the term "superstructure" is applied to polymers and proteins to describe ordering on a length scale larger than that of monomeric segments.