Infinite critical boson non-Fermi liquid

Abstract

We study a novel type of non-Fermi liquid where there exist an infinite number of critical bosonic modes instead of finite bosonic modes for the conventional ones. We consider itinerant magnets with both conduction electrons and fluctuating magnetic moments in three dimensions. With Dzyaloshinskii-Moriya interaction, the moments fluctuate near a boson surface in the reciprocal space at low energies when the system approaches an ordering transition. The infinite number of critical modes on the boson surface strongly scatter the infinite gapless electrons on the Fermi surface and convert the metallic sector into a non-Fermi liquid. We explain the novel physical properties of this non-Fermi liquid. On the ordered side, a conventional non-Fermi liquid emerges due to the scattering by the gapless Goldstone mode from the spontaneous breaking of the global rotational symmetry. We discuss the general structure of the phase diagram in the vicinity of the quantum phase transition and clarify various crossover behaviors.

Probing a Bose Metal via Electrons: Inescapable non-Fermi liquid scattering and pseudogap physics

“…Since the states along the blue lines cover a broad range of energy, the fermionic poles are always broadened even down to the chemical potential. This enhanced phase space for scattering is even more effective than the typical NFL scenario, which involves scattering against bosons of well-defined momentum [58][59][60]. Furthermore, since the Bose metal is a stable phase composed of real bosons (with fixed density), the effect of coupling is actually strengthened in the low-temperature limit or far away from a phase boundary.…”

Infinite critical boson induced non-Fermi liquid in $d=3-ε$ dimensions

“…Approaching the lower energies ω < ω Ld , the Landau damping effect gradually sets in. In such a critical regime, Hertz method has been used to address the non-Fermi liquid behavior in the presence of the CBS 20 . In the present study, we focus on the finite energy regime ω > ω Ld ; our goal is to establish non-singular effective theory and explore possible perturbative NFL fixed points.…”

“…The stable existence of a critical boson surface has been studied in the context of Bose Luttinger liquids 14,15 and the so-called "Bose metal" [16][17][18] . Various NFL-behaviors are proposed by coupling fermions to the critical boson surfaces 15,[19][20][21][22] . Conventional theoretical treatments focus on the deep infrared regime around the quantum critical point, which then provides information for the mediated finite temperature sector.…”

“…To get access to the quantum criticality, a well-established method proposed by J. Hertz 23 and A. J. Millis 24 relies on integrating out the gapless fermions first; as a result, a singular polarization function is generated for bosons which alters the spacetimes scaling. In a previous paper 20 , one of us follows this line of thinking and develops a Hertz-Millis theory for Fermi surface coupled to the critical boson surface (CBS) in d = 3 + 1 dimensions.…”

Probing a Bose metal via electrons: inescapable non-Fermi liquid scattering and pseudogap physics

“…Since the states along the blue lines cover a broad range of energy, the fermionic poles are always broadened even down to the chemical potential. This enhanced phase space for scattering is even more effective than the typical NFL scenario, which involves scattering against bosons of well-defined momentum [65][66][67]. Furthermore, since the Bose metal is a stable phase composed of real bosons (with fixed density), the effect of coupling is actually strengthened in the low-temperature limit or far away from a phase boundary.…”