Imaging of integer quantum Hall edge state in a quantum point contact via scanning gate microscopy

Abstract

Integer quantum Hall edge states have been imaged in the constriction region of a quantum point contact fabricated in an InGaAs heterostructure at high magnetic fields using low-temperature scanning gate microscopy (SGM). Features in the SGM images grew wider and deeper as side gates squeezed the constriction. Furthermore, clear plateaus corresponding to the depopulation of edge states were observed. We propose a model for these images based on the variation of the local confinement potential induced by the tip.