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

doi:10.1016/S0169-4332(02)01493-9

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 journal › Article › peer-review

4 Scopus citations

Abstract

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 language	English (US)
Pages (from-to)	134-139
Number of pages	6
Journal	Applied Surface Science
Volume	210
Issue number	1-2 SPEC.
DOIs	https://doi.org/10.1016/S0169-4332(02)01493-9
State	Published - Mar 31 2003
Externally published	Yes

Keywords

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

ASJC Scopus subject areas

Condensed Matter Physics
Surfaces, Coatings and Films
Surfaces and Interfaces

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10.1016/S0169-4332(02)01493-9

Cite this

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title = "Imaging coherent electron flow in a two-dimensional electron gas",

abstract = "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.",

keywords = "GaAs, Quantum point contact, Scanning probe microscopy, Two-dimensional electron gas",

author = "LeRoy, {B. J.} and Topinka, {M. A.} and Bleszynski, {A. C.} and Westervelt, {R. M.} and Shaw, {S. E.J.} and Heller, {E. J.} and Maranowski, {K. D.} and Gossard, {A. C.}",

note = "Funding Information: This work was supported at Harvard by ONR grant N00014-95-1-0104, by the NSF through the Nanoscale Science and Engineering Center grants PHY-0117795 and CHE-9610501, and at the University of California at Santa Barbara by the NSF Science and Technology Center QUEST.",

year = "2003",

month = mar,

day = "31",

doi = "10.1016/S0169-4332(02)01493-9",

language = "English (US)",

volume = "210",

pages = "134--139",

journal = "Applied Surface Science",

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number = "1-2 SPEC.",

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TY - JOUR

T1 - Imaging coherent electron flow in a two-dimensional electron gas

AU - LeRoy, B. J.

AU - Topinka, M. A.

AU - Bleszynski, A. C.

AU - Westervelt, R. M.

AU - Shaw, S. E.J.

AU - Heller, E. J.

AU - Maranowski, K. D.

AU - Gossard, A. C.

N1 - Funding Information: This work was supported at Harvard by ONR grant N00014-95-1-0104, by the NSF through the Nanoscale Science and Engineering Center grants PHY-0117795 and CHE-9610501, and at the University of California at Santa Barbara by the NSF Science and Technology Center QUEST.

PY - 2003/3/31

Y1 - 2003/3/31

N2 - 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.

AB - 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.

KW - GaAs

KW - Quantum point contact

KW - Scanning probe microscopy

KW - Two-dimensional electron gas

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EP - 139

JO - Applied Surface Science

JF - Applied Surface Science

IS - 1-2 SPEC.

ER -

Imaging coherent electron flow in a two-dimensional electron gas

Abstract

Keywords

ASJC Scopus subject areas

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