Effect of Electron-Phonon Interaction Range for a Half-Filled Band in One Dimension

TL;DR

This paper uses quantum Monte Carlo simulations to study how the range of electron-phonon interactions affects phases and correlations in a one-dimensional half-filled band, revealing suppression of charge correlations with longer interaction ranges.

Contribution

It introduces a simulation approach for nonlocal fermion-boson models at finite filling and maps the phase diagram across interaction ranges in one dimension.

Findings

Suppression of $2k_F$ charge correlations with increasing interaction range.

Identification of metallic, Peierls, and phase-separated regions.

Power-law decay of charge correlations similar to pairing correlations.

Abstract

We demonstrate that fermion-boson models with nonlocal interactions can be simulated at finite band filling with the continuous-time quantum Monte Carlo method. We apply this method to explore the influence of the electron-phonon interaction range for a half-filled band in one dimension, covering the full range from the Holstein to the Fr\"ohlich regime. The phase diagram contains metallic, Peierls, and phase-separated regions, which we characterize in terms of static and dynamical correlation functions. In particular, our results reveal a suppression of $2k_F$ charge correlations with increasing interaction range, allowing for a power-law decay comparable to the pairing correlations.