Thermal averages in a quantum point contact with a single coherent wave packet

E. J. Heller, K. E. Aidala, Brian J Leroy, A. C. Bleszynski, A. Kalben, R. M. Westervelt, K. D. Maranowski, A. C. Gossard

Research output: Contribution to journalArticle

21 Citations (Scopus)

Abstract

A novel formal equivalence between thermal averages of coherent properties (e.g., conductance) and time averages of a single wave packet arises for Fermi gases and certain geometries. In the case of one open channel in a quantum point contact (QPC), only one wave packet history, with the wave packet width equal to the thermal length, completely determines the thermally averaged conductance. The formal equivalence moreover allows very simple physical interpretations of interference features surviving under thermal averaging. Simply put, pieces of the thermal wave packet returning to the QPC along independent paths must arrive at the same time in order to interfere. Remarkably, one immediate result of this approach is that higher temperature leads to narrower wave packets and therefore better resolution of events in the time domain. In effect, experiments at 4.2 K are performing time-gated experiments at better than a gigahertz. Experiments involving thermally averaged ballistic conductance in 2DEGS are presented as an application of this picture.

Original languageEnglish (US)
Pages (from-to)1285-1292
Number of pages8
JournalNano Letters
Volume5
Issue number7
DOIs
StatePublished - Jul 2005
Externally publishedYes

Fingerprint

Wave packets
Point contacts
wave packets
equivalence
Experiments
Ballistics
ballistics
Gases
Hot Temperature
histories
interference
Geometry
geometry
gases

ASJC Scopus subject areas

  • Materials Science(all)
  • Electronic, Optical and Magnetic Materials
  • Chemistry (miscellaneous)

Cite this

Heller, E. J., Aidala, K. E., Leroy, B. J., Bleszynski, A. C., Kalben, A., Westervelt, R. M., ... Gossard, A. C. (2005). Thermal averages in a quantum point contact with a single coherent wave packet. Nano Letters, 5(7), 1285-1292. https://doi.org/10.1021/nl0504585

Thermal averages in a quantum point contact with a single coherent wave packet. / Heller, E. J.; Aidala, K. E.; Leroy, Brian J; Bleszynski, A. C.; Kalben, A.; Westervelt, R. M.; Maranowski, K. D.; Gossard, A. C.

In: Nano Letters, Vol. 5, No. 7, 07.2005, p. 1285-1292.

Research output: Contribution to journalArticle

Heller, EJ, Aidala, KE, Leroy, BJ, Bleszynski, AC, Kalben, A, Westervelt, RM, Maranowski, KD & Gossard, AC 2005, 'Thermal averages in a quantum point contact with a single coherent wave packet', Nano Letters, vol. 5, no. 7, pp. 1285-1292. https://doi.org/10.1021/nl0504585
Heller EJ, Aidala KE, Leroy BJ, Bleszynski AC, Kalben A, Westervelt RM et al. Thermal averages in a quantum point contact with a single coherent wave packet. Nano Letters. 2005 Jul;5(7):1285-1292. https://doi.org/10.1021/nl0504585
Heller, E. J. ; Aidala, K. E. ; Leroy, Brian J ; Bleszynski, A. C. ; Kalben, A. ; Westervelt, R. M. ; Maranowski, K. D. ; Gossard, A. C. / Thermal averages in a quantum point contact with a single coherent wave packet. In: Nano Letters. 2005 ; Vol. 5, No. 7. pp. 1285-1292.
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