Combined spontaneous symmetry-breaking and symmetry-protected topological order from cluster charge interaction

TL;DR

This paper demonstrates the coexistence of symmetry-protected topological order and symmetry-breaking Kekul$ ext{é}$ valence bond order in a correlated electron system, revealing a novel interaction-driven topological phase transition with unique Green's function features.

Contribution

It provides the first large-scale quantum Monte Carlo study showing combined topological and symmetry-breaking phases in the Kane-Mele model with cluster charge interactions.

Findings

Coexistence of topological order and Kekul$ ext{é}$ valence bond order.

Interaction-driven topological phase transition with Green's function zeros.

No mean-field correspondence for the observed transition.

Abstract

The study of symmetry-protected topological states in presence of electron correlations has recently aroused great interest as rich and exotic phenomena can emerge. Here, we report a concrete example by employing large-scale unbiased quantum Monte Carlo study of the Kane-Mele model with cluster charge interactions. The ground-state phase diagram for the model at half filling is established. Our simulation identifies the coexistence of a symmetry-protected topological order with a symmetry-breaking Kekul$\acute{e}$ valence bond order and shows that the spontaneous symmetry-breaking is accompanied by an interaction-driven topological phase transition (TPT). This TPT features appearance of zeros of single-particle Green's function and gap closing in spin channel rather than single-particle excitation spectrum, and thus has no mean-field correspondence.