Imaging fringes in magnetic focusing of electron waves

ORAL

Abstract

Magnetic focusing of the electron flow between two quantum point contacts (QPCs) in a two-dimensional electron gas (2DEG) in a GaAs/AlGaAs heterostructure occurs when the QPC spacing is an integer multiple of the diameter of a cyclotron orbit. Images of magnetic focusing taken with a cooled scanning probe microscope (SPM) exhibit fringes when multiple paths of electrons interfere, as well as branching of the electron paths caused by small angle scattering [1]. We use simulations to show that one could improve images of fringe structures by using devices smaller than the length required to form branches. The distance between QPCs can be made quite small ($\sim $~0.5 microns) without destroying the fringe structure. We plan to test our simulations using double QPC devices. \newline \newline [1] Kathy Aidala\textit{ et al.}~ to be published (2007).

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Authors

  • Melaku Muluneh

    Harvard University

  • Robert M. Westervelt

    Dept of Physics and Div of Engineering \& Applied Sciences, Harvard Univ, Dept of Physics and Div of Eng and App Sci, Harvard Univ, Harvard University, Mallinckrodt Professor of Applied Physics and of Physics, Department of Physics, Harvard University, Cambridge, MA, Harvard DEAS, Department of Physics

  • Rob Parrott

    Harvard University

  • Eric Heller

    Harvard University, Harvard University Department of Physics

  • Micah Hanson

    UC Santa Barbara, UCSB

  • Arthur Gossard

    Materials Department, University of California, Santa Barbara, Materials Dept., UCSB, UC Santa Barbara, Univ. California, Santa Barbara, University of California, Santa Barbara, UCSB