Self-consistent calculation of the electron distribution near a Quantum-Point Contact in the integer Quantum Hall Effect

Abstract

In this work we implement the self-consistent Thomas-Fermi-Poisson approach to a homogeneous two dimensional electron system (2DES). We compute the electrostatic potential produced inside a semiconductor structure by a quantum-point-contact (QPC) placed at the surface of the semiconductor and biased with appropriate voltages. The model is based on a semi-analytical solution of the Laplace equation. Starting from the calculated confining potential, the self-consistent (screened) potential and the electron densities are calculated for finite temperature and magnetic field. We observe that there are mainly three characteristic rearrangements of the incompressible "edge" states, which will determine the current distribution near a QPC.