Hall Potential Profiles in Quantum Hall Samples Measured by a Low-Temperature Scanning Force Microscope

摘要

Our measurements of the Hall potential distribution in GaAs/AlGaAs quantum Hall samples using a scanning force microscope at a temperature of 1.4 K are reviewed. The results emphasize the important role of compressible and incompressible strips, running along the edges of the two-dimensional electron system (2DES), for the quantum Hall effect. At the interface line between the 2DES and its alloyed metal contact with good ohmic behavior, a partial depletion of the electron concentration in the 2DES in front of contact is identified, causing for certain magnetic field regimes an incompressible strip lying in parallel to the interface line and therefore isolating the compressible 2DES bulk from the 2DES edge with the contact.