Correlation-driven branch in doped excitonic insulators

TL;DR

This paper uses matrix-product-state methods to study doped excitonic insulators, revealing a correlation-driven in-gap spectral branch linked to excitonic correlations, which could serve as an indicator of electron-hole interactions.

Contribution

It introduces a numerical approach to identify a doping-induced in-gap branch associated with excitonic correlations in doped one-dimensional insulators.

Findings

Discovery of a correlation-driven in-gap branch in doped excitonic insulators.

The in-gap branch is linked to excitonic correlations and can serve as an indicator.

Numerical methods reveal the propagation dynamics underlying the in-gap feature.

Abstract

We investigate the spectral properties of doped one-dimensional excitonic insulators. Employing matrix-product-state-based methods, we compute the single-particle spectrum and optical conductivity in a correlated two-band model. Our numerical calculation reveals the emergence of a correlation-driven in-gap branch in the doped state. The origin of the in-gap branch is examined by decomposing the propagation dynamics of a single particle, elucidating that the doping-induced branch is associated with excitonic correlations. Our demonstrations suggest that the doping-induced branch can serve as an indicator of electron-hole correlations.