What is measured in the scanning gate microscopy of a quantum point contact?

Abstract

The conductance change due to a local perturbation in a phase-coherent nanostructure is calculated. The general expressions to first and second order in the perturbation are applied to the scanning gate microscopy of a two-dimensional electron gas containing a quantum point contact. The first-order correction depends on two scattering states with electrons incoming from opposite leads and is suppressed on a conductance plateau; it is significant in the step regions. On the plateaus, the dominant second-order term likewise depends on scattering states incoming from both sides. It is always negative, exhibits fringes, and has a spatial decay consistent with experiments.

4 pages, 1 figure, final version

References in corpus (6)

• Imaging Electron Wave Functions Inside Open Quantum Rings
• Electron interferometer formed with a scanning probe tip and quantum point contact
• Local Density of States in Mesoscopic Samples from Scanning Gate Microscopy
• Imaging Electron Interferometer
• Scanning Gate Microscopy of a Nanostructure where Electrons Interact
• Detection of interaction-induced nonlocal effects using perfectly transmitting nanostructures

Cited by in corpus (2)

• On the imaging of electron transport in semiconductor quantum structures by scanning-gate microscopy: successes and limitations
• Multitip scanning gate microscopy for ballistic transport studies in systems with two-dimensional electron gas