Critical quasiparticles in single-impurity and lattice Kondo models

TL;DR

This paper reviews recent advances in understanding quantum criticality involving critical quasiparticles in single-impurity and lattice Kondo models, with implications for Dirac materials and heavy-fermion systems.

Contribution

It provides a comprehensive review of quantum phase transitions in impurity and lattice Kondo models, highlighting the role of critical quasiparticles in these phenomena.

Findings

Impurity models with pseudogapped hosts show unique quantum critical behavior.

Heavy-fermion lattice models exhibit strong-coupling near antiferromagnetic quantum phase transitions.

Critical quasiparticles are central to understanding quantum criticality in these systems.

Abstract

Quantum criticality in systems of local moments interacting with itinerant electrons has become an important and diverse field of research. Here we review recent results which concern (a) quantum phase transitions in single-impurity Kondo and Anderson models and (b) quantum phase transitions in heavy-fermion lattice models which involve critical quasiparticles. For (a) the focus will be on impurity models with a pseudogapped host density of states and their applications, e.g., in graphene and other Dirac materials, while (b) is devoted to strong-coupling behavior near antiferromagnetic quantum phase transitions, with potential applications in a variety of heavy-fermion metals.