Global Magnetic Phase Diagram and Local Quantum Criticality in Heavy Fermion Metals

TL;DR

This paper explores the magnetic phase diagram of heavy fermion metals, proposing two classes of quantum critical points characterized by Fermi surface changes and local quantum criticality, supported by experimental insights.

Contribution

It introduces a comprehensive phase diagram with distinct quantum critical points based on Fermi surface properties and local quantum criticality in heavy fermion systems.

Findings

Identification of two classes of quantum critical points.

Evidence for Fermi surface jumps at quantum criticality.

Implications for non-orthodox quantum critical behavior.

Abstract

We address the global magnetic phase diagram of Kondo lattice systems. Through the distinct Fermi surface properties of the various phases at zero temperature, we argue that the phase diagram supports two classes of quantum critical point. One of these describes a direct transition from a magnetic metal phase with localized f-electrons to a paramagnetic one with itinerant f-electrons. This result provides the context for the picture of local quantum criticality, in which the Fermi surface jumps across the quantum critical point and the quasiparticle residue vanishes as the quantum critical point is approached from either side. Some of the unusual experiments, concerning the phases and quantum critical points of heavy fermion metals, are discussed from the present perspective. These developments have implications in broader contexts. In particular, they form a part of the growing evidence for quantum criticality that goes beyond the orthodox description in terms of order-parameter fluctuations.