Enhancement of Kondo effect in multilevel quantum dots

Research output: Contribution to journalArticle

45 Citations (Scopus)


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
Issue number1
Publication statusPublished - 2005 Jan 1


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

ASJC Scopus subject areas

  • Physics and Astronomy(all)

Fingerprint Dive into the research topics of 'Enhancement of Kondo effect in multilevel quantum dots'. Together they form a unique fingerprint.

  • Cite this