d_{x^2-y^2} Symmetry and the Pairing Mechanism

TL;DR

This paper investigates how different electron-phonon interactions influence d_{x^2-y^2} pairing symmetry in high-temperature cuprates, providing insights into the underlying pairing mechanism through theoretical analysis.

Contribution

It analyzes the impact of various electron-phonon interactions on d_{x^2-y^2} pairing within an RPA framework of the 2D Hubbard model, highlighting conditions favoring this pairing symmetry.

Findings

Interactions increasing with momentum transfer favor d_{x^2-y^2} pairing.

Positive interactions at larger momentum transfers promote the pairing symmetry.

Results suggest specific electron-phonon interactions support high-temperature superconductivity.

Abstract

An important question is if the gap in the high temperature cuprates has d_{x^2-y^2} symmetry, what does that tell us about the underlying interaction responsible for pairing. Here we explore this by determining how three different types of electron-phonon interactions affect the d_{x^2-y^2} pairing found within an RPA treatment of the 2D Hubbard model. These results imply that interactions which become more positive as the momentum transfer increases favor d_{x^2-y^2} pairing in a nearly half-filled band.