Imaging Electron Flow From a Quantum Point Contact

ORAL

Abstract

We image electron flow from a quantum point contact (QPC) into a high-mobility two-dimensional electron gas (2DEG) using scanning gate microscopy (SGM). We note two surprising phenomena, which we compare with results from simulations: 1. The beam of electrons immediately leaving the QPC is unexpectedly narrow and collimated. 2. Under certain conditions, the signal generally associated with current flow density (i.e. the change in differential conductance due to scattering from the scanning gate tip) can change sign from negative to positive.

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Authors

  • M. P. Jura

  • M. A. Topinka

  • A. R. Sciambi

    • Stanford University

  • David Goldhaber-Gordon

    • Stanford University
    • Dept. of Physics, Stanford University

  • L. Urban

    • University of Illinois at Urbana-Champaign

  • Ali Yazdani

    • Princeton University
    • Princeton Nanocale Microscopy Laboratory, Department of Physics, Princeton University
    • Princeton Nanoscale Microscopy Laboratory, Department of Physics, Princeton University

  • H. Shtrikman

    • Weizmann Institute of Science

  • L. N. Pfeiffer

  • K. W. West

    • Bell Labs, Lucent Technologies