Superconductivity Fluctuations in a One-dimensional Two Band Electron-Phonon Model with Strong Repulsive Interactions

TL;DR

This paper investigates how electron-phonon interactions influence superconductivity fluctuations in a one-dimensional two-band model with strong electron-electron repulsions, revealing a region where singlet superconductivity dominates.

Contribution

It demonstrates the emergence of dominant singlet superconductivity fluctuations due to electron-phonon coupling in a strongly repulsive, multi-band one-dimensional system.

Findings

Superconductivity fluctuations are dominant in certain parameter regions.

Electron-phonon interactions enable superconductivity despite strong repulsive interactions.

The dominant fluctuations occur at large U and V values.

Abstract

We study a one-dimensional, two band model with short range electron-electron repulsions (onsite $U$ and nearest-neighbour $V$ terms) and electron-phonon coupling. We show that there is a region of $U$,$V$ and band filling in which singlet superconductivity fluctuations are dominant. This region is absent without electron-phonon interactions and includes large values of $U$,$V$.