Z_2 Gauge Theory of Electron Fractionalization in the t,t'-J Model

TL;DR

This paper demonstrates that in a 2+1D t,t'-J model with uniaxial anisotropy, electron fractionalization occurs via Z_2 gauge fields, leading to a spin-charge-separated liquid phase, contrasting with U(1) gauge theories.

Contribution

It establishes the equivalence of the t,t'-J model to Z_2 gauge theories, revealing a new phase with frozen Z_2 gauge fluctuations and spin-charge separation.

Findings

Identification of Z_2 gauge fields in the model

Existence of a spin-charge-separated liquid phase

Contrast with U(1) gauge field behavior

Abstract

We consider a strongly correlated "t,t'-J" spin model with a positive uniaxial anisotropy. We show that in 2+1 dimensions, this model is equivalent to spin-charge excitations coupled to Z_2 Ising gauge fields and not to a U(1) gauge fields (as in the "t-J" model). As a result a phase of frozen Z_2 gauge fluctuations is possible, giving rise to a spin-charge-separated liquid.