Glassy dynamics of electrons near the metal-insulator transition

This review first describes the evidence that strongly suggests the existence of the metal-insulator transition (MIT) in a two-dimensional electron system in Si regardless of the amount of disorder. Extensive studies of the charge dynamics demonstrate that this transition is closely related to the glassy freezing of electrons as temperature T->0. Similarities to the behavior of three-dimensional materials raise the intriguing possibility that such correlated dynamics might be a universal feature of the MIT regardless of the dimensionality.