ENSEMBLE DENSITY-FUNCTIONAL THEORY FOR INHOMOGENEOUS FRACTIONAL QUANTUM HALL SYSTEMS

The fractional quantum Hall effect (FQHE) occurs at a certain magnetic held strengths B(n) in a two-dimensional electron gas of density n a t strong magnetic fields perpendicular to the plane of the electron ga s. At these magnetic fields strengths, the system is incompressible, i .e., there is a finite cost in energy for creating charge density fluc tuations in the bulk, while the boundary of the electron gas has gaple ss modes of density waves. The bulk energy gap arises because of the s trong electron-electron interactions. While there are very good models for infinite homogeneous systems and for the gapless excitations of t he boundary of the electron gas, computational methods to accurately m odel finite, inhomogeneous systems with more than about 10 electrons h ave not been available until very recently. We will here review an ens emble density functional approach to studying the ground state of larg e inhomogeneous spin-polarized FQHE systems. (C) 1996 John Wiley & Son s, Inc.