Enhancement of Kondo effect in multilevel quantum dots

研究成果: Article査読

47 被引用数 (Scopus)

抄録

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.

本文言語English
ページ(範囲)95-102
ページ数8
ジャーナルJournal of the Physical Society of Japan
74
1
DOI
出版ステータスPublished - 2005 1月

ASJC Scopus subject areas

  • 物理学および天文学(全般)

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