Imaging coherent electron flow

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

Research output: Chapter in Book/Report/Conference proceedingConference contribution

4 Citations (Scopus)

Abstract

Images of electron flow through a two-dimensional electron gas from a quantum point contact (QPC) can be obtained at liquid He temperatures using scanning probe microscopy (SPM). A negatively charged SPM tip depletes the electron gas immediately below it and decreases the conductance by backscattering electrons. Images of electron flow are obtained by recording the conductance as the tip is scanned over the sample. These images show angular patterns that are characteristic of electron flow through individual modes of the QPC, as well as well- defined branches at longer distances. The addition of a prism formed by a triangular gate bends electron paths as the electron density is reduced under the prism by an applied gate voltage. Under the conditions of the experiment, electron-electron scattering is the dominant inelastic process. By observing how the amplitude of backscattered electrons in images of electron flow decreases with added electron energy, we are able to determine the average length and time necessary for inelastic scattering. A dc voltage V0 applied across the QPC accelerates electrons so that their energy is greater than the Fermi energy before inelastic scattering occurs. The signal is observed to decrease in amplitude and eventually disappear at distances from the QPC that decrease progressively as V0 is increased.

Original languageEnglish (US)
Title of host publicationInstitute of Physics Conference Series
EditorsA.R. Long, J.H. Davies
Pages169-176
Number of pages8
Volume171
StatePublished - 2003
Externally publishedYes
EventPhysics of Semiconductors 2002 - Proceedings of the 26th International Conference on the Physics of Semiconductors - Edinburgh, United Kingdom
Duration: Jul 29 2002Aug 2 2002

Other

OtherPhysics of Semiconductors 2002 - Proceedings of the 26th International Conference on the Physics of Semiconductors
CountryUnited Kingdom
CityEdinburgh
Period7/29/028/2/02

Fingerprint

electrons
prisms
electron gas
inelastic scattering
microscopy
electron trajectories
scanning
probes
electric potential
backscattering
electron scattering
recording
electron energy
energy
liquids
temperature

ASJC Scopus subject areas

  • Physics and Astronomy(all)

Cite this

Leroy, B. J., Bleszynski, A. C., Topinka, M. A., Westervelt, R. M., Shaw, S. E. J., Heller, E. J., ... Gossard, A. C. (2003). Imaging coherent electron flow. In A. R. Long, & J. H. Davies (Eds.), Institute of Physics Conference Series (Vol. 171, pp. 169-176)

Imaging coherent electron flow. / Leroy, Brian J; Bleszynski, A. C.; Topinka, M. A.; Westervelt, R. M.; Shaw, S. E J; Heller, E. J.; Maranowski, K. D.; Gossard, A. C.

Institute of Physics Conference Series. ed. / A.R. Long; J.H. Davies. Vol. 171 2003. p. 169-176.

Research output: Chapter in Book/Report/Conference proceedingConference contribution

Leroy, BJ, Bleszynski, AC, Topinka, MA, Westervelt, RM, Shaw, SEJ, Heller, EJ, Maranowski, KD & Gossard, AC 2003, Imaging coherent electron flow. in AR Long & JH Davies (eds), Institute of Physics Conference Series. vol. 171, pp. 169-176, Physics of Semiconductors 2002 - Proceedings of the 26th International Conference on the Physics of Semiconductors, Edinburgh, United Kingdom, 7/29/02.
Leroy BJ, Bleszynski AC, Topinka MA, Westervelt RM, Shaw SEJ, Heller EJ et al. Imaging coherent electron flow. In Long AR, Davies JH, editors, Institute of Physics Conference Series. Vol. 171. 2003. p. 169-176
Leroy, Brian J ; Bleszynski, A. C. ; Topinka, M. A. ; Westervelt, R. M. ; Shaw, S. E J ; Heller, E. J. ; Maranowski, K. D. ; Gossard, A. C. / Imaging coherent electron flow. Institute of Physics Conference Series. editor / A.R. Long ; J.H. Davies. Vol. 171 2003. pp. 169-176
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