Anisotropic electron-phonon interaction in the cuprates

TL;DR

This paper investigates how different phonon modes in cuprates affect electron spectral functions, revealing mode-specific coupling behaviors that align with experimental ARPES observations, especially in the superconducting state.

Contribution

It introduces a symmetry-based, kinematic approach to distinguish electron-phonon interactions in cuprates, highlighting mode-specific effects on spectral functions.

Findings

Out-of-plane O buckling mode couples strongly near the anti-node.

In-plane Cu-O breathing modes couple strongly near the node.

Band renormalizations are most pronounced in the superconducting state.

Abstract

We explore manifestations of electron-phonon coupling on the electron spectral function for two phonon modes in the cuprates exhibiting strong renormalizations with temperature and doping. Applying simple symmetry considerations and kinematic constraints, we find that the out-of-plane, out-of-phase O buckling mode (B_1g) involves small momentum transfers and couples strongly to electronic states near the anti-node while the in-plane Cu-O breathing modes involve large momentum transfers and couples strongly to nodal electronic states. Band renormalization effects are found to be strongest in the superconducting state near the anti-node, in full agreement with angle-resolved photoemission spectroscopy (ARPES) data.