Kondo effect in coupled quantum dots under magnetic fields

2001/04/05 by Tomosuke Aono, Mikio Eto
Physics and Astronomy · #cond-mat.mes-hall

paper · pdf · doi:10.1103/physrevb.64.073307

published as Phys. Rev. B 64, 073307 (2001) · 6 pages, 3 figures

arxiv created 2001/04/05 · arxiv updated 2009/11/30

Abstract

The Kondo effect in coupled quantum dots is investigated theoretically under magnetic fields. We show that the magnetoconductance (MC) illustrates peak structures of the Kondo resonant spectra. When the dot-dot tunneling coupling V_C is smaller than the dot-lead coupling Δ (level broadening), the Kondo resonant levels appear at the Fermi level (E_F). The Zeeman splitting of the levels weakens the Kondo effect, which results in a negative MC. When V_C is larger than Δ, the Kondo resonances form bonding and anti-bonding levels, located below and above E_F, respectively. We observe a positive MC since the Zeeman splitting increases the overlap between the levels at E_F. In the presence of the antiferromagnetic spin coupling between the dots, the sign of MC can change as a function of the gate voltage.

Related

• Kondo effect in quantum dots coupled to ferromagnetic leads
• Chessboard magnetoconductance of a quantum dot in the Kondo regime
• Anomalous Kondo Spin Splitting in Quantum Dots
• Kondo Effect in the Presence of Itinerant-Electron Ferromagnetism Studied with the Numerical Renormalization Group Method
• Magnetic field-induced Kondo effects in Coulomb blockade systems