In solid-state physics
, when describing crystal structure
, a supercell
is a repeating unit cell
of the crystal that contains several primitive cells
. In some cases, these primitive cells of the underlying crystal are perturbed so that the supercell becomes the new primitive cell.
For example, in body-centered (bcc) or face-centered (fcc) cubic crystals, the primitive cell is a parallelepiped or rhombohedron, respectively, but the conventional unit cell used to describe these structures is a simple-cubic supercell.
Supercells are also commonly used in computational models of crystal defects, in order to allow the use of periodic boundary conditions.