PHASE-SEPARATION OF EDGE STATES IN THE INTEGER QUANTUM HALL REGIME

Coulomb effects on the edge states of a two-dimensional electron gas i n the presence of a high magnetic field are studied for different widt hs of the boundaries. Schrodinger and Poisson equations are self-consi stently solved in the integer quantum Hall regime. Regions of flat ban ds at the Fermi level appear for smooth interfaces in order to minimiz e the electrostatic energy and are related to the existence of dipoles induced by the magnetic field. These plateaus determine the phase sep aration in stripes of compressible and incompressible electron liquids .