Quasiparticles and quantum phase transition in universal low-temperature properties of heavy-fermion metals

TL;DR

This paper explains the universal low-temperature phase diagram of heavy-fermion metals like CeCoIn5 using quasiparticles and fermion condensation quantum phase transition, linking quasiparticle stability to non-Fermi liquid behavior.

Contribution

It introduces a theory based on fermion condensation quantum phase transition to explain universal properties of heavy-fermion metals, emphasizing quasiparticle robustness.

Findings

Quasiparticles remain well-defined above FCQPT.

The theory accurately reproduces experimental phase diagrams.

Fermion condensation suppresses critical fluctuations.

Abstract

We demonstrate, that the main universal features of the low temperature experimental $H-T$ phase diagram of CeCoIn5 and other heavy-fermion metals can be well explained using Landau paradigm of quasiparticles. The main point of our theory is that above quasiparticles form so-called fermion-condensate state, achieved by a fermion condensation quantum phase transition (FCQPT). When a heavy fermion liquid undergoes FCQPT, the fluctuations accompanying above quantum critical point are strongly suppressed and cannot destroy the quasiparticles. The comparison of our theoretical results with experimental data on CeCoIn5 have shown that the electronic system of above substance provides a unique opportunity to study the relationship between quasiparticles properties and non-Fermi liquid behavior.