Behavior of Fermi Systems Approaching Fermion Condensation Quantum Phase Transition from Disordered Phase

TL;DR

This paper investigates how Fermi systems behave near the fermion condensation quantum phase transition, showing that the effective mass diverges and the system exhibits Fermi liquid behavior with specific properties preserved.

Contribution

It demonstrates the universal divergence of quasiparticle effective mass near FCQPT in both 2D and 3D systems, and describes the transition from highly correlated to conventional Fermi liquid behavior.

Findings

Effective mass diverges as $1/|x-x_{FC}|$ near FCQPT

Fermi liquid behavior persists with finite effective mass

Wiedemann-Franz law and Kadowaki-Woods ratio are maintained

Abstract

The behavior of Fermi systems which approach the fermion condensation quantum phase transition (FCQPT) from the disordered phase is considered. We show that the quasiparticle effective mass $M^*$ diverges as $M^*\propto 1/|x-x_{FC}|$ where $x$ is the system density and $x_{FC}$ is the critical point at which FCQPT occurs. Such a behavior is of general form and takes place in both three dimensional (3D) systems and two dimensional (2D) ones. Since the effective mass $M^*$ is finite, the system exhibits the Landau Fermi liquid behavior. At $|x-x_{FC}|/x_{FC}\ll 1$, the behavior can be viewed as a highly correlated one, because the effective mass is large and strongly depends on the density. In case of electronic systems the Wiedemann-Franz law is held and Kadowaki-Woods ratio is preserved. Beyond the region $|x-x_{FC}|/x_{FC}\ll 1$, the effective mass is approximately constant and the system becomes conventional Landau Fermi liquid.