Anomalous magnetic splitting of the Kondo resonance

TL;DR

This paper uses the exact Bethe-ansatz solution to analyze how magnetic fields split the Kondo resonance in quantum dots, revealing the effects of strong correlations on spectral features and transport properties.

Contribution

It provides explicit formulas for the shift and broadening of Kondo peaks and discusses limitations of large-N approaches at finite magnetic fields.

Findings

Significant low-temperature reduction of peak splitting due to strong correlations

Explicit formulas for Kondo peak shift and broadening

Implications for transport experiments in quantum dots

Abstract

The splitting of the Kondo resonance in the density of states of an Anderson impurity in finite magnetic field is calculated from the exact Bethe-ansatz solution. The result gives an estimate of the electron spectral function for nonzero magnetic field and Kondo temperature, with consequences for transport experiments on quantum dots in the Kondo regime. The strong correlations of the Kondo ground state cause a significant low-temperature reduction of the peak splitting. Explicit formulae are found for the shift and broadening of the Kondo peaks. A likely cause of the problems of large-N approaches to spin-1/2 impurities at finite magnetic field is suggested.