SU(2) gauge theory of fluctuating stripe order in the two-dimensional Hubbard model

TL;DR

This paper develops an SU(2) gauge theory for fluctuating stripe order in the 2D Hubbard model, explaining pseudogap phenomena and Fermi arc structures through fractionalized electron operators and spin-charge separation.

Contribution

It introduces a novel SU(2) gauge theoretical framework with fractionalized electrons to describe stripe order and pseudogap phases in the Hubbard model.

Findings

Charge ordered pseudogap phase with a reconstructed Fermi surface

Spectral functions show Fermi arcs in various Brillouin zone regions

Spinons prevent SU(2) spin symmetry breaking at finite temperature

Abstract

We present an SU(2) gauge theory of fluctuating stripe order in the two-dimensional Hubbard model. The theory is based on a fractionalization of the electron operators in fermionic chargons with a pseudospin degree of freedom, and charge neutral spinons capturing fluctuations of the spin orientation. The chargons are treated in a renormalized mean-field theory. We focus on regions of the phase diagram where they undergo stripe order. The spinons are described by a non-linear sigma model with pseudospin stiffnesses determined by the chargons. They prevent breaking of the physical SU(2) spin symmetry at any finite temperature, resulting in a charge ordered pseudogap phase with a reconstructed Fermi surface and a spin gap. The spectral function for single-particle excitations exhibits a collection of Fermi arcs and other structures. The arcs appear in various regions of the Brillouin zone, but never exclusively around the Brillouin zone diagonals.