Composite Weyl semimetal as a parent state for three dimensional topologically ordered phases

TL;DR

This paper introduces (3+1)D models of strongly correlated electrons forming a critical state with relativistic neutral fermions and emergent gauge fields, leading to exotic topologically ordered phases with potential surface states.

Contribution

It presents a new class of (3+1)D models that realize a strongly correlated Weyl semimetal as a parent state for topologically ordered phases.

Findings

Identification of a critical state with relativistic neutral fermions and gauge fields.

Prediction of instabilities leading to gapless and gapped topologically ordered phases.

Description of fractionalized electronic insulators with potential non-trivial surface states.

Abstract

We introduce (3+1) dimensional models of short-range-interacting electrons that form a strongly correlated many-body state whose low-energy excitations are relativistic neutral fermions coupled to an emergent gauge field, $\text{QED}_{4}$. We discuss the properties of this critical state and its instabilities towards exotic phases such as a gapless `composite' Weyl semimetal and fully gapped topologically ordered phases that feature anyonic point-like as well as line-like excitations. These fractionalized phases describe electronic insulators. They may be further enriched by symmetries which results in the formation of non-trivial surface states.