Kondo effect in an Antiferromagnetic metal

TL;DR

This paper investigates how a spin-1/2 impurity behaves in an antiferromagnetic metal, revealing that Kondo effects persist but with a partially unscreened moment, depending on impurity location and magnetization.

Contribution

It demonstrates that Kondo singularities can occur in antiferromagnetic metals with spin non-conserving interactions, showing the conditions for partial screening and residual moments.

Findings

Kondo singularities occur in antiferromagnetic metals with non-conserving spin interactions.

Residual unscreened magnetic moments depend on impurity position and magnetization.

Kondo effect is only fully realized at points with zero local magnetization.

Abstract

We study the fate of a spin-1/2 impurity in the itinerant antiferromagnetic metallic phase via a renormalization group analysis and a variational calculation. The local moment - conduction electron interaction hamiltonian in an antiferromagnetic metal is spin non-conserving. We show that for a general location of the impurity, the Kondo singularities still occur, but the ground state has a partially unscreened moment. We calculate the magnitude of this residual moment and the variation of the spin polarization with energy for a substitutional impurity as a function of the staggered magnetization. The usual Kondo effect only occurs if the impurity is placed at points where the magnetization is zero.