From itinerant to local-moment antiferromagnetism in Kondo lattices: Adiabatic continuity vs. quantum phase transitions

TL;DR

This paper explores how Kondo lattices can transition smoothly from itinerant to local-moment antiferromagnetism, challenging the notion that such changes always involve quantum phase transitions, and discusses implications for experiments and theory.

Contribution

It demonstrates the possibility of a continuous evolution between different magnetic states in Kondo lattices, contrasting with the common expectation of quantum phase transitions.

Findings

Continuous evolution from itinerant to local-moment antiferromagnetism is possible.

Topological changes of the Fermi surface can occur without phase transitions.

Discussions on criteria for topological transitions in antiferromagnetic phases.

Abstract

Motivated by both experimental and theoretical activities, we discuss the fate of Kondo screening and possible quantum phase transitions in antiferromagnetically ordered phases of Kondo lattices. While transitions with topological changes of the Fermi surface may occur, we demonstrate that an entirely continuous evolution from itinerant to local-moment antiferromagnetism (i.e. from strong to negligible Kondo screening) is possible as well. This situation is in contrast to that in a non-symmetry-broken situation where a quantum phase transition towards an exotic metallic spin-liquid state necessarily accompanies the disappearance of Kondo screening. We discuss criteria for the existence of topological transitions in the antiferromagnetic phase, as well as implications for theoretical scenarios and for current experiments.