SU(2) gauge theory of the pseudogap phase in the two-dimensional Hubbard model

TL;DR

This paper develops an SU(2) gauge theory for the pseudogap phase in the 2D Hubbard model, capturing magnetic fluctuations and features like Fermi arcs and nematicity, relevant for high-Tc cuprates.

Contribution

It introduces a fractionalized electron model with gauge fluctuations that explains pseudogap phenomena in the Hubbard model.

Findings

Magnetic chargon order leads to pseudogap features

Spinon fluctuations prevent magnetic long-range order at finite temperature

The theory reproduces key experimental features of high-Tc cuprates

Abstract

We present a SU(2) gauge theory of fluctuating magnetic order in the two-dimensional Hubbard model. The theory is based on a fractionalization of electrons in fermionic chargons and bosonic spinons. The chargons undergo N\'eel or spiral magnetic order below a density dependent transition temperature $T^*$. Fluctuations of the spin orientation are described by a non-linear sigma model obtained from a gradient expansion of the spinon action. The spin stiffnesses are computed from a renormalization group improved random phase approximation. Our approximations are applicable for a weak or moderate Hubbard interaction. The spinon fluctuations prevent magnetic long-range order of the electrons at any finite temperature. The phase with magnetic chargon order exhibits many features characterizing the pseudogap regime in high-$T_c$ cuprates: a strong reduction of charge carrier density, a spin gap, Fermi arcs, and electronic nematicity.