FRACTIONAL QUANTUM HALL-EFFECT IN THICK LAYERS AND DOUBLE QUANTUM-WELL SYSTEMS

We study the fractional quantum Hall effect in a thick quasi-two-dimensional layer and a double quantum well system by finite-size numerical calculation. In the thick-layer system, we find that the fractional quantum Hall effect will be destroyed due to the weakening of the short-range component of the repulsive electron-electron interaction. In a double quantum well system, we investigate the interplay between the inter-well tunneling and the inter-particle correlation and find that the competition between them determines the properties of the ground state. Most interestingly, we predict the existence of a nu = 1/2 quantum Hall effect in a double-well system.