Breakdown of conductance quantization in quantum point contacts with realistic impurity potentials

A. M. Zagoskin, Sergey Rashkeev, R. I. Shekhter, G. Wendin

Research output: Contribution to journalArticle

15 Citations (Scopus)

Abstract

The breakdown of conductance quantization in a quantum point contact in the presence of a random long-range impurity potential is discussed. It is shown that in the linear response regime a decisive role is played by the indirect backscattering mechanism via quasilocalized states at the Fermi level, this can provide a much higher backscattering rate than any direct backscattering process. For realistic contact lengths (<or=2000 nm) the scattering processes prove to be independent, in spite of the coherence of the electron wave. The distribution function of conductance fluctuations is obtained by direct numerical calculations as well as being estimated within an analytical model for the first time. It is shown to be a generalized Poisson distribution. Estimates are made for quantum point contact performance at different choices of parameters. In particular, it is better the larger the intermode distance is compared to the amplitude of the random impurity potential.

Original languageEnglish
Article number009
Pages (from-to)6253-6270
Number of pages18
JournalJournal of Physics: Condensed Matter
Volume7
Issue number31
DOIs
Publication statusPublished - 1 Dec 1995
Externally publishedYes

Fingerprint

Poisson Distribution
Point contacts
Backscattering
backscattering
breakdown
Electrons
Impurities
impurities
Poisson distribution
Fermi level
Distribution functions
Analytical models
distribution functions
Scattering
estimates
scattering
electrons

ASJC Scopus subject areas

  • Condensed Matter Physics
  • Electronic, Optical and Magnetic Materials

Cite this

Breakdown of conductance quantization in quantum point contacts with realistic impurity potentials. / Zagoskin, A. M.; Rashkeev, Sergey; Shekhter, R. I.; Wendin, G.

In: Journal of Physics: Condensed Matter, Vol. 7, No. 31, 009, 01.12.1995, p. 6253-6270.

Research output: Contribution to journalArticle

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