Imaging coherent electron flow in a two-dimensional electron gas

B. J. LeRoy, M. A. Topinka, A. C. Bleszynski, R. M. Westervelt, S. E.J. Shaw, E. J. Heller, K. D. Maranowski, A. C. Gossard

Research output: Contribution to journalArticlepeer-review

4 Scopus citations


Scanning probe microscopy (SPM) has been used to obtain images of electron flow through a two-dimensional electron gas from a quantum point contact (QPC) inside a GaAs/AlGaAs heterostructure at liquid He temperatures. A negatively charged SPM tip depletes the electron gas immediately below and decreases the conductance of the QPC by backscattering electrons. Images of electron flow are obtained by recording the conductance, as the tip is scanned across the structure. At distances less than 1μm from the QPC, the electron flow shows angular lobes that are characteristic of the quantum modes of the QPC. At distances greater than 1 μm, well-defined branches of electron flow are observed that are caused by the cumulative effects of small angle scattering by ionized donor and impurity atoms. Interference fringes spaced by half the Fermi wavelength decorate all of the images of electron flow; their spacing gives a spatial profile of the electron density.

Original languageEnglish (US)
Pages (from-to)134-139
Number of pages6
JournalApplied Surface Science
Issue number1-2 SPEC.
StatePublished - Mar 31 2003


  • GaAs
  • Quantum point contact
  • Scanning probe microscopy
  • Two-dimensional electron gas

ASJC Scopus subject areas

  • Chemistry(all)
  • Condensed Matter Physics
  • Physics and Astronomy(all)
  • Surfaces and Interfaces
  • Surfaces, Coatings and Films


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