Enhancement of phonon effects in photoexcited states of one-dimensional Mott insulators

TL;DR

This study investigates how electron correlation influences electron-phonon interactions in 1D Mott insulators, revealing that Coulomb repulsion enhances phonon effects on excitons, improving agreement with experimental spectra.

Contribution

It demonstrates that increasing on-site Coulomb repulsion enhances phonon effects on excitons in 1D Mott insulators, contrasting with its suppressive effect on ground state Peierls instability.

Findings

EP interaction effect on excitons is enhanced by Coulomb repulsion.

DMRG calculations align better with experimental spectra when EP interaction is included.

Coulomb repulsion suppresses Peierls instability but enhances phonon effects on excitons.

Abstract

We examine how the electron correlation affects the electron-phonon (EP) interaction in the linear optical absorption spectrum of the one-dimensional (1D) extended Hubbard-Holstein model. A density matrix renormalization group (DMRG) calculation shows that the effect of the EP interaction on an exciton is enhanced by increasing the on-site Coulomb repulsion. This enhancement is in contrast to the effect of the EP interaction on the ground state where the Peierls instability is suppressed by the on-site Coulomb repulsion. The DMRG data with the EP interaction fit with absorption experiments in 1D cuprates better than those for the extended Hubbard model.