Preformed heavy-electrons at the Quantum Critical Point in heavy fermion compounds

TL;DR

This paper proposes an incoherent heavy-fermion scenario involving soft modes with dynamical exponent z=3, explaining non-Fermi liquid behavior near quantum critical points in heavy fermion compounds, and discusses a crossover to z=1.

Contribution

It introduces a novel incoherent heavy-fermion framework with soft modes of z=3, providing insights into non-Fermi liquid physics at quantum critical points.

Findings

Inelastic scattering with soft modes leads to non-Fermi liquid behavior.

A crossover from z=3 to z=1 occurs due to quantum phase fluctuations.

The scenario explains experimental observations in heavy fermion compounds.

Abstract

The existence of multiple energy scales is regarded as a signature of the Kondo breakdown mechanism for explaining the quantum critical behavior of certain heavy fermion compounds, like YbRh$_{2}$Si$_{2}$. The nature of the intermediate state between the heavy Fermi liquid and the quantum critical region, however, remains elusive. In this study we suggest an incoherent heavy-fermion scenario, where inelastic scattering with novel soft modes of the dynamical exponent $z = 3$ gives rise to non-Fermi liquid physics for thermodynamics and transport despite the formation of the heavy-fermion band. We discuss a crossover from $z = 3$ to $z = 1$ for quantum phase fluctuations.