Exact diagonalization study of the two-dimensional t-J-Holstein model

TL;DR

This study uses exact diagonalization to analyze the two-dimensional t-J-Holstein model, revealing a phase transition from delocalized to localized states influenced by electron-phonon coupling, with implications for pairing susceptibility.

Contribution

It introduces a method to incorporate full phonon mode dynamics in the 2D t-J-Holstein model using a truncated momentum space approach.

Findings

Identifies a phase transition at finite electron-phonon coupling.

Shows suppression of pairing susceptibility due to e-ph coupling.

Demonstrates the effectiveness of phonon mode truncation in modeling.

Abstract

We study by exact diagonalization the two-dimensional t-J-Holstein model near quarter filling by retaining only few phonon modes in momentum space. This truncation allows us to incorporate the full dynamics of the retained phonon modes. The behavior of the kinetic energy, the charge structure factor and other physical quantities, show the presence of a transition from a delocalized phase to a localized phase at a finite value of the electron-phonon coupling. We have also given some indications that the e-ph coupling leads in general to a suppression of the pairing susceptibility at quarter filling.