Relevance of phonon dynamics in strongly correlated systems coupled to phonons: A Dynamical Mean Field Theory analysis

TL;DR

This study uses Dynamical Mean Field Theory to analyze how strong electronic repulsion influences phonon dynamics and electron-phonon interactions in correlated systems, revealing energy-dependent effects relevant for high-temperature superconductors.

Contribution

It provides new insights into the non-trivial, energy-dependent renormalization of electron-phonon coupling caused by Coulomb repulsion in strongly correlated materials.

Findings

Large Coulomb repulsion reduces low-energy electron-phonon effects

High-energy properties are less affected by Coulomb repulsion

Phonon frequency strongly influences coupling renormalization

Abstract

The properties of the electron-phonon interaction in the presence of a sizable electronic repulsion at finite doping are studied by investigating the metallic phase of the Hubbard-Holstein model with Dynamical Mean Field Theory. Analyzing the quasiparticle weight at finite doping, we find that a large Coulomb repulsion reduces the effect of electron-phonon coupling at low-energy, while this reduction is not present at high energy. The renormalization of the electron-phonon coupling induced by the Hubbard repul sion depends in a surprisingly strong and non-trivial way on the phonon frequency. Our results suggest that phonon might affect differently high-energy and low-energy properties and this, together with the effect of phonon dynamics, should be carefully taken into account when the effects of the electron-phonon interaction in a strongly correlated system, like the superconducting cuprates, are discussed.