Low-frequency edge magnetoplasmons in the quantum Hall regime under conditions of reduced Coulomb interaction

Abstract
The authors have measured edge magnetoplasmon oscillations (EMP) in a high-mobility GaAs-GaAlAs heterostructure in the quantum Hall regime. By placing a ground plane close to the two-dimensional electron gas the electrostatic field far from the edge is screened. By varying the separation of the ground plane from the 2DEG the distance that the electrostatic fields penetrates from the edge can be varied. The relative importance of the edge and bulk contributions to the EMP are thus deduced and one is able to estimate the width of the EMP charge distribution in the QHE regime as 1 mu m. The authors attribute this width as being due to the characteristic site of the random potential near the edge of the 2DEG.