Wigner crystal

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A Wigner crystal is the solid (crystalline) phase of electrons first predicted by Eugene Wigner in 1934. Such a phase can be realized if the electron density is sufficiently low. Wigner, infact, predicted that electrons crystallize and form a lattice if the density of the electron gas (2D, or 3D) is under a critical value. This is due to the fact that correlations between electrons became higher than kinetic energies and dominate the electronic structure. The critical density value (or the inverse of mean radius between the electrons) is lower for 3-dimensional gasses than 2-dimensional. In 2-dimension (2D), it can also be realized by applying a sufficiently strong perpendicular magnetic field.