Anomalous Behavior of the Spin Susceptibility of Strongly Correlated Fermi Systems

TL;DR

This paper explores the failure of Fermi-liquid theory in strongly correlated Fermi systems, revealing a quantum phase transition that modifies spin susceptibility behavior, including a Curie-Weiss component near the critical density.

Contribution

It identifies a quantum phase transition causing the breakdown of Fermi-liquid theory and modifies the quasiparticle distribution to explain the anomalous spin susceptibility behavior.

Findings

Spin susceptibility exhibits a Curie-Weiss component near the critical density.

The Weiss temperature vanishes at the quantum critical point.

Fermi-liquid theory fails in the studied density region.

Abstract

The spin susceptibility $\chi(T)$ of strongly correlated Fermi systems is investigated in the density region where Fermi-liquid theory fails. We attribute this failure to a specific quantum phase transition associated with a rearrangement of the Landau state at low temperatures $T$, retaining the assumption that the Landau quasiparticle picture survives in a generic sense. Taking into account the resulting modification of the quasiparticle istribution function, the spin susceptibility $\chi(T)$ is shown to contain a Curie-Weiss component $\chi_{\rm CW}(T)\sim (T-\Theta_{\rm W})^{-1}$, with the Weiss temperature $\Theta_{\rm W}$ vanishing at the critical density for the transition.