Enhancement of Kondo effect in multilevel quantum dots

Research output: Contribution to journalArticle

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Abstract

We theoretically study enhancement mechanisms of the Kondo effect in multilevel quantum dots. In quantum dots fabricated on semiconductors, the energy difference between discrete levels Δ is tunable by applying a magnetic field. With two orbitals and spin 1/2 in the quantum dots, we evaluate the Kondo temperature T K as a function of Δ, using the scaling method. T K is maximal around Δ = 0 and decreases with increasing |Δ|, following a power law, T K(Δ) = T K(0)·(T K(0)/|Δ|) γ, which is understood as a crossover from SU(4) to SU(2) Kondo effect. The exponents on both sides of a level crossing, γ L and γ R, satisfy a relation of γ L·γ R = 1. We compare this enhanced Kondo effect with that by spin-singlet-triplet degeneracy for an even number of electrons, to explain recent experimental results using vertical quantum dots.

Original languageEnglish
Pages (from-to)95-102
Number of pages8
JournalJournal of the Physical Society of Japan
Volume74
Issue number1
DOIs
Publication statusPublished - 2005 Jan

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Kondo effect
quantum dots
augmentation
crossovers
exponents
scaling
orbitals
magnetic fields
electrons
temperature
energy

Keywords

  • Kondo effect
  • Multilevel
  • Quantum dot
  • Scaling method
  • SU(4) Kondo effect

ASJC Scopus subject areas

  • Physics and Astronomy(all)

Cite this

Enhancement of Kondo effect in multilevel quantum dots. / Eto, Mikio.

In: Journal of the Physical Society of Japan, Vol. 74, No. 1, 01.2005, p. 95-102.

Research output: Contribution to journalArticle

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