THE FRACTIONAL HALL-EFFECT IN MULTICOMPONENT SYSTEMS

The fractional Hall effect is a consequence of the existence of incompressible states of a two-dimensional (2D) electron gas at certain fractional Landau level filling factors. In multicomponent systems a rich variety of novel incompressible states can be realized. It is now becoming possible to study these states in systems where the magnetic field is weak enough to allow partial spin polarization, or where two or more 2D electron layers are in close proximity. Some of the new issues in the physics of multi-component systems are discussed. © 1990.