SU(2) Gauge Theory for Fluctuating Stripes in the Pseudogap Regime

We investigate the role of charge order in a pseudogap described by an SU(2) gauge theory of fluctuating magnetic order. The theory is based on a fractionalization of electrons into a fermionic chargon pseudospinor and a bosonic spinon, which leads to an emergent SU(2) pseudospin symmetry. In the mean-field solution of the 2D Hubbard model, which we use to describe the electrons in the copper-oxygen planes, Neel, spiral, or stripe order were observed below a density dependent transition temperature T^∗ [1]. 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 random phase approximation for the chargon susceptibility. The spinon fluctuations prevent magnetic long-range order of the electrons at any finite temperature. The phase with magnetic chargon order exhibits the most salient features characterizing the pseudogap regime in high-Tc cuprates: a strong reduction of charge carrier density, a spin gap, and Fermi arcs [2], and we set out to observe the effects of charge order in this context.

[1] R. Scholle, P. M. Bonetti, D. Vilardi, W. Metzner, PRB 108 035139 (2023);

[2] P. M. Bonetti, W. Metzner, PRB 106, 205152 (2022).