Theory of electron-phonon interactions in extended correlated systems probed by resonant inelastic x-ray scattering

TL;DR

This paper uses advanced computational methods to analyze how resonant inelastic x-ray scattering (RIXS) reveals electron-phonon interactions in correlated quantum materials, offering insights for interpreting experimental data.

Contribution

It presents a detailed theoretical study of RIXS spectra in the Hubbard-Holstein model using DMRG, highlighting differences from traditional models and improving understanding of $e$-ph interactions.

Findings

RIXS spectra differ significantly from Lang-Firsov model predictions.

The study clarifies how RIXS encodes electron-phonon interactions.

Results inform more accurate analysis of experimental RIXS data.

Abstract

An emerging application of resonant inelastic x-ray scattering (RIXS) is the study of lattice excitations and electron-phonon ($e$-ph) interactions in quantum materials. Despite the growing importance of this area of research, the community lacks a complete understanding of how the RIXS process excites the lattice and how these excitations encode information about the $e$-ph interactions. Here, we present a detailed study of the RIXS spectra of the Hubbard-Holstein model defined on extended one-dimensional lattices. Using the density matrix renormalization group (DMRG) method, we compute the RIXS response while treating the electron mobility, many-body interactions, and core-hole interactions on an equal footing. The predicted spectra exhibit notable differences from those obtained using the commonly adopted Lang-Firsov models, with important implications for analyzing past and future experiments. Our results provide a deeper understanding of how RIXS probes $e$-ph interactions and set the stage for a more realistic analysis of future experiments.