Local quantum critical point and non-Fermi liquid properties

TL;DR

This paper reviews recent theoretical advances in understanding local quantum critical points, emphasizing their role in explaining non-Fermi liquid behavior in correlated electron systems and comparing predictions with experiments.

Contribution

It introduces the concept of local quantum criticality using extended dynamical mean field theory and Ginzburg-Landau arguments, advancing the theoretical framework for quantum critical points in metals.

Findings

Consistent explanation of non-Fermi liquid phenomena in heavy fermion metals

Predictions for neutron scattering, NMR, and Hall effect measurements

Analogies drawn between quantum criticality and Mott transitions

Abstract

Quantum criticality provides a means to understand the apparent non-Fermi liquid phenomena in correlated electron systems. How to properly describe quantum critical points in electronic systems has however been poorly understood. The issues have become particularly well-defined due to recent experiments in heavy fermion metals, in which quantum critical points have been explicitly identified. In this paper, I summarize some recent theoretical work on the subject, with an emphasis on the notion of ``local quantum criticality''. I describe the microscopic work based on an extended dynamical mean field theory, as well as Ginzburg-Landau arguments for the robustness of the local quantum critical point beyond the microscopics. I also present the consequences of this picture on the inelastic neutron scattering, NMR, Fermi surface properties and Hall coefficient, and compare them with the available experiments. Some analogies with the Mott transition phenomena are also noted.