Coulomb crystal

Coulomb crystal

[′kü‚läm ‚krist·əl] (atomic physics) A crystalline array that is formed from laser-cooled ions stored in an electromagnetic trap and in which the relative positions of the ions are approximately fixed and are determined by the balance between the confining forces of the trap and the Coulomb repulsion of the ions. Also known as ion crystal. (cryogenics) A structure formed by electrons trapped at a liquid helium surface at sufficiently high electron densities and low temperatures, in which the electrons occupy the points of a two-dimensional hexagonal lattice.