Abstract

Conductance fluctuations associated with transport through quantum-dot systems are currently understood to depend on the nature of the corresponding classical dynamics, i.e., integrable or chaotic. However, we find that in graphene quantum-dot systems, when a magnetic field is present, signatures of classical dynamics can disappear and universal scaling behaviors emerge. In particular, as the Fermi energy or the magnetic flux is varied, both regular oscillations and random fluctuations in the conductance can occur, with alternating transitions between the two. By carrying out a detailed analysis of two types of integrable (hexagonal and square) and one type of chaotic (stadium) graphene dot system, we uncover a universal scaling law among the critical Fermi energy, the critical magnetic flux, and the dot size. We develop a physical theory based on the emergence of edge states and the evolution of Landau levels (as in quantum Hall effect) to understand these experimentally testable behaviors.

Original languageEnglish (US)
Article number245448
JournalPhysical Review B - Condensed Matter and Materials Physics
Volume85
Issue number24
DOIs
StatePublished - Jun 28 2012

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Magnetic flux
Fermi level
Graphene
Semiconductor quantum dots
magnetic flux
graphene
quantum dots
Quantum Hall effect
Stadiums
Scaling laws
quantum Hall effect
scaling laws
signatures
Magnetic fields
scaling
oscillations
energy
magnetic fields

ASJC Scopus subject areas

  • Condensed Matter Physics
  • Electronic, Optical and Magnetic Materials

Cite this

Conductance fluctuations in graphene systems : The relevance of classical dynamics. / Ying, Lei; Huang, Liang; Lai, Ying-Cheng; Grebogi, Celso.

In: Physical Review B - Condensed Matter and Materials Physics, Vol. 85, No. 24, 245448, 28.06.2012.

Research output: Contribution to journalArticle

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