Interplay between the mesoscopic Stoner and Kondo effects in quantum dots

Abstract

We consider electrons confined to a quantum dot interacting antiferromagnetically with a spin-$\half$ Kondo impurity. The electrons also interact among themselves ferromagnetically with a dimensionless coupling $\tilde{J}$, where $\tilde{J}=1$ denotes the bulk Stoner transition. We show that as $\tilde{J}$ approaches 1 there is a regime with enhanced Kondo correlations, followed by one where the Kondo effect is destroyed and impurity is spin polarized opposite to the dot electrons. The most striking signature of the first, Stoner-enhanced Kondo regime, is that a Zeeman field increases the Kondo scale, in contrast to the case for noninteracting dot electrons. Implications for experiments are discussed.

4 pages, 2 eps figures. Revised version contains comments on the subtleties of the large-N approach to the Kondo problem, and the possibility of a smooth crossover instead of a transition. Three references added. Figures unchanged

References in corpus (8)

• Tunable Non-local Spin Control in a Coupled Quantum Dot System
• Spin and Polarized Current from Coulomb Blockaded Quantum Dots
• Kondo screening cloud effects in mesoscopic devices
• Transport through quantum dots in mesoscopic circuits
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Cited by in corpus (8)

• Spectroscopy of the Kondo Problem in a Box
• Theoretical study of electronic transport through a small quantum dot with a magnetic impurity
• Spin-orbit interaction in quantum dots in the presence of exchange correlations
• Mesoscopic Stoner instability in metallic nanoparticles revealed by shot noise
• Ground State and Excitations of Quantum Dots with "Magnetic Impurities"
• Analyzing the measured phase in the multichannel Aharonov-Bohm interferometer
• Interacting Quantum Dot Coupled to a Kondo Spin: A Universal Hamiltonian Study
• The strong-coupling limit of a Kondo spin coupled to a mesoscopic quantum dot: effective Hamiltonian in the presence of exchange correlations