Magnetic field induced quantum phase transitions in the two-impurity Anderson model

TL;DR

This paper investigates how a local magnetic field can induce a quantum phase transition in the two-impurity Anderson model, restoring the Kondo effect and revealing a continuous transition with diverging susceptibilities.

Contribution

It demonstrates that a magnetic field can induce a continuous quantum phase transition in the two-impurity Anderson model, highlighting the role of local criticality.

Findings

Magnetic field restores the Kondo resonance.

Transition is continuous with diverging susceptibilities.

Supports the local critical scenario in Kondo systems.

Abstract

In the two-impurity Anderson model, the inter-impurity spin exchange interaction favors a spin singlet state between two impurities leading to the breakdown of the Kondo effect. We show that a local uniform magnetic field can delocalize the quasiparticles to restore the Kondo resonance. This transition is found to be continuous, accompanied by not only the divergence of the staggered (antiferromagnetic) susceptibility, but also the divergence of the uniform spin susceptibility. This may imply that the magnetic field induced quantum phase transitions in Kondo systems are in favor of the local critical type.