Conductance stability in chaotic and integrable quantum dots with random impurities

Guanglei Wang, Lei Ying, Ying-Cheng Lai

Research output: Contribution to journalArticle

3 Citations (Scopus)

Abstract

For a quantum dot system of fixed geometry, in the presence of random impurities the average conductance over an appropriate range of the Fermi energy decreases as the impurity strength is increased. Can the nature of the corresponding classical dynamics in the dot region affect the rate of decrease? Utilizing graphene quantum dots with two semi-infinite, single-mode leads as a prototypical model, we address the device stability issue by investigating the combined effects of classical dynamics and impurities on the average conductance over the energy range of the first transverse mode. We find that, for chaotic dot systems, the rate of decrease in the average conductance with the impurity strength is in general characteristically smaller than that for integrable dots. We develop a semiclassical analysis for the phenomenon and also obtain an understanding based on the random matrix theory. Our results demonstrate that classical chaos can generally lead to a stronger stability in the device performance, strongly advocating exploiting chaos in the development of nanoscale quantum transport devices.
Original languageEnglish
Article number022901
Number of pages10
JournalPhysical Review. E, Statistical, Nonlinear and Soft Matter Physics
Volume92
Issue number2
DOIs
Publication statusPublished - 3 Aug 2015

Keywords

  • Conductance stability
  • quantum dots
  • random impurities

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