Scanning gate measurements in the quantum Hall regime at 300 mK

Scanning gate measurements have been performed on a shallow two-dimensional electron gas in a Ga[Al]As heterostructure in the quantum Hall regime at 300 mK. This technique uses the local electrostatic potential induced by the conducting tip of a scanning force microscope for influencing the resistance of mesoscopic structures. Applied at high magnetic fields and low temperatures on a Hall bar sample, it is a further development of previous backscattering experiments with spatially immobile gates. This technique gives insight into the nature of the states in the interior and at the edges of a Hall bar with a width of 4 mum. (C) 2003 Elsevier B.V. All rights reserved.