Spin density wave, Fermi liquid, and fractionalized phases in a theory of antiferromagnetic metals using paramagnons and bosonic spinons

TL;DR

This paper develops a gauge theory involving bosonic spinons and fermions to describe the pseudogap phase in cuprates, capturing fractionalization, phase transitions, and Fermi surface changes.

Contribution

It introduces a novel gauge theory framework with fractionalized paramagnons to explain the pseudogap phase and related quantum phase transitions in antiferromagnetic metals.

Findings

Describes small Fermi surfaces violating Luttinger volume.

Identifies phases with Fermi liquid and spin density wave order.

Analyzes electronic spectra across quantum phase transitions.

Abstract

The pseudogap metal phase of the hole-doped cuprates can be described by small Fermi surfaces of electron-like quasiparticles, which enclose a volume violating the Luttinger relation. This violation requires the existence of additional fractionalized excitations which can be viewed as fractionalized remnants of the paramagnon. We fractionalize the paramagnon into bosonic spinons, and present a gauge theory of bosonic spinons, a Higgs field, and an ancilla layer of fermions coupled to the original electrons. Along with the small Fermi surface metal, this theory displays conventional phases: the Fermi liquid with a low-energy paramagnon mode, and phases with spin density wave order. We follow the evolution of the electronic photoemission spectrum across these quantum phase transitions. We consider both the two-sublattice N\'eel and incommensurate spin density wave phases.