Exotic spin, charge and pairing correlations of the two-dimensional doped Hubbard model: a symmetry entangled mean-field approach

TL;DR

This study uses a symmetry entangled mean-field approach to explore complex spin, charge, and pairing correlations in the doped 2D Hubbard model, revealing a crossover from antiferromagnetism to stripe order and fragmented pairing interactions.

Contribution

It introduces a symmetry restoration method in mean-field calculations to better capture interaction effects in the Hubbard model without symmetry breaking.

Findings

Crossover from incommensurate antiferromagnetism to stripe order with doping.

Identification of fragmented pairing modes including d-wave and exotic channels.

Symmetry entanglement accounts for significant interaction effects.

Abstract

Intertwining of spin, charge and pairing correlations in the repulsive two-dimensional Hubbard model is shown through unrestricted variational calculations, with projected wavefunctions free of symmetry breaking. A crossover from incommensurate antiferromagnetism to stripe order naturally emerges in the hole-doped region when increasing the on-site coupling. Although effective pairing interactions are identified, they are strongly fragmented in several modes including d-wave pairing and more exotic channels related to an underlying stripe. We demonstrate that the entanglement of a mean-field wavefunction by symmetry restoration can largely account for interaction effects.