Excitonic insulators as a model of $d-d$ and Mott transitions in strongly correlated materials

TL;DR

This paper proposes a model using excitonic insulators to understand $d-d$ and Mott transitions in strongly correlated materials, highlighting the role of Van-Hove singularities and connecting to resonating-valence-bond physics.

Contribution

It introduces a microscopic excitonic insulator framework that links inter- and intra-band ordering phenomena and emphasizes the significance of Van-Hove singularities in these transitions.

Findings

Van-Hove singularity nesting drives ordering transitions

Connection established between excitonic insulators and resonating-valence-bond physics

Clarification of the role of excitons in strongly correlated materials

Abstract

We show how strongly correlated materials could be described within the framework of an excitonic insulator formalism, and delineate the relationship between inter- and intra-band ordering phenomena. Our microscopic model of excitons clarifies the fundamental role of Van-Hove-singularity-nesting in driving both inter- and intra-band ordering transitions, and uncovers an interesting connection with resonating-valence-bond physics.