Magnetic field effects in few-level quantum dots: theory, and application to experiment

Abstract

We examine several effects of an applied magnetic field on Anderson-type models for both single- and two-level quantum dots, and make direct comparison between numerical renormalization group (NRG) calculations and recent conductance measurements. On the theoretical side the focus is on magnetization, single-particle dynamics and zero-bias conductance, with emphasis on the universality arising in strongly correlated regimes; including a method to obtain the scaling behavior of field-induced Kondo resonance shifts over a very wide field range. NRG is also used to interpret recent experiments on spin-1/2 and spin-1 quantum dots in a magnetic field, which we argue do not wholly probe universal regimes of behavior; and the calculations are shown to yield good qualitative agreement with essentially all features seen in experiment. The results capture in particular the observed field-dependence of the Kondo conductance peak in a spin-1/2 dot, with quantitative deviations from experiment occurring at fields in excess of $\sim$ 5 T, indicating the eventual inadequacy of using the equilibrium single-particle spectrum to calculate the conductance at finite bias.

15 pages, 12 figures. Version as published in PRB

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Cited by in corpus (16)

• Spin-1/2 Kondo effect in an InAs nanowire quantum dot: the Unitary limit, conductance scaling and Zeeman splitting
• Local moment formation and Kondo screening in impurity trimers
• At which magnetic field, exactly, does the Kondo resonance begin to split? A Fermi liquid description of the low-energy properties of the Anderson model
• Spin-polarized conductance in double quantum dots: Interplay of Kondo, Zeeman and interference effects
• Common non-Fermi liquid phases in quantum impurity physics
• Nonequilibrium Kondo effect in a magnetic field: Auxiliary master equation approach
• Numerical Renormalization Group calculations of the magnetization of isotropic and anisotropic Kondo impurities
• Regular and singular Fermi liquid in triple quantum dots: Coherent transport studies
• Validity of the local self-energy approximation: Application to coupled quantum impurities
• Dynamic response of a spin-1/2 Kondo singlet
• Scaling of conductance through quantum dots with magnetic field
• Renormalization-group analysis of a spin-1 Kondo dot: Non-equilibrium transport and relaxation dynamics
• Magnetic field induced mixed-level Kondo effect in two-level systems
• Functional renormalization group study of parallel double quantum dots: Effects of asymmetric dot-lead couplings
• Zero-field splitting of the Kondo resonance and quantum criticality in triple quantum dots
• Magnetization curves of deposited finite spin chains