Relativistic non-Fermi liquid from interacting birefringent fermions: A robust superuniversality

TL;DR

This paper explores quantum critical phenomena in birefringent fermions near Mott transitions, revealing a universal relativistic non-Fermi liquid behavior characterized by a unique terminal velocity and strong collective excitations.

Contribution

It demonstrates that diverse symmetry-breaking transitions lead to a universal relativistic non-Fermi liquid regime with a single terminal velocity, applicable to various strongly correlated Dirac materials.

Findings

Existence of a unique terminal velocity near quantum critical points.

Presence of a relativistic non-Fermi liquid with vanishing quasiparticle weight.

Universality of the non-Fermi liquid behavior across different symmetry-breaking classes.

Abstract

We address the emergent quantum critical phenomena for (pseudo)spin-3/2 birefringent fermions, featuring two effective Fermi velocities, when they reside close to itinerant Mott transitions realized through spontaneous symmetry breaking and triggered by strong local or Hubbardlike repulsive interactions. Irrespective of the nature of the mass orderings that produce fully gapped quasiparticle spectra in the ordered phase, which otherwise can be grouped into three classes, the system always possesses a \emph{unique} terminal velocity near the corresponding quantum critical point. The associated critical regime accommodates a relativistic non-Fermi liquid of strongly coupled collective bosonic and spin-1/2 Dirac excitations with vanishing weight of the quasiparticle pole. These conclusions are also operative near superconducting critical points. Therefore, relativistic non-Fermi liquid possibly constitutes a robust superuniversal description for the entire family of strongly correlated arbitrary half-integer spin Dirac materials.