Direct Determination of Electron-Phonon Coupling Matrix Element in a Correlated System

TL;DR

This study introduces a method to directly measure the electron-phonon coupling matrix element in anisotropic correlated systems using high-resolution spectroscopy data, advancing understanding of EPC in complex materials.

Contribution

The paper presents a novel scheme combining electron energy loss and photoemission spectroscopy to directly determine the full electron-phonon coupling matrix element in correlated systems.

Findings

Successfully measured momentum-dependent phonon linewidths and dispersions.

Developed a general method for resolving EPC matrix elements.

Applied the method to a cuprate superconductor.

Abstract

High-resolution electron energy loss spectroscopy measurements have been carried out on an optimally doped cuprate Bi2Sr2CaCu2O8+{\delta}. The momentum-dependent linewidth and the dispersion of an A1 optical phonon are obtained. Based on these data as well as the detailed knowledge of the electronic structure from angle-resolved photoemission spectroscopy, we develop a scheme to determine the full structure of electron-phonon coupling for a specific phonon mode, thus providing a general method for directly resolving the EPC matrix element in systems with anisotropic electronic structures.