Unified First-Principles Formula for Time-Resolved ARPES Spectra of Coherent and Incoherent Excitons

TL;DR

This paper introduces a comprehensive first-principles formula for analyzing time-resolved ARPES spectra, enabling detailed understanding of both coherent and incoherent excitons across various experimental conditions.

Contribution

It presents a unified, microscopic framework that connects excitonic dynamics to observable spectral features, applicable beyond low-density regimes.

Findings

Derived a general formula for time-resolved photoemission spectra.

Applicable across different temperatures, densities, and delays.

Provides a predictive tool for excitonic dynamics in complex materials.

Abstract

Despite major experimental progresses in time-resolved and angle-resolved photoemission spectroscopy, a quantitative, microscopic framework for interpreting exciton-induced modifications of electronic band structures -- applicable even beyond the low-density limit -- is still lacking. Here we close this gap by introducing a unified approach that links the dynamics of coherent and incoherent excitons to distinct and experimentally observable excitonic sidebands. Our central result is a general, first-principles formula for time-resolved photoemission spectra, applicable across a broad range of temperatures, excitation densities, and pump-probe delays. This advance provides a predictive tool for quantitatively tracking excitonic dynamics in complex materials.