NONEQUILIBRIUM TRANSPORT ALONG AN EDGE OF VARIABLE SLOPE IN THE FRACTIONAL QUANTUM HALL REGIME

We have performed an experimental investigation of equilibration betwe en edge states in the fractional quantum Hall regime. We have develope d a technique to alter the electrostatic potential at the edge continu ously and controllably from a smooth to a sharp potential gradient, us ing a set of gates. A non-equilibrium current distribution in the edge states is created which then travels along the edge to a detector. Th e scattering between the various fractional edge states is investigate d, and a method developed to calculate scattering probabilities betwee n pairs of edge states, revealing independent 1/5, 1/3 and 2/5 edge st ates, for a bulk filling factor of 2/3. Equilibrium is found to depend strongly on the potential slope. (C) 1998 Elsevier Science B.V. All r ights reserved.