Many-Body Correlation Effects in Fr\"ohlich Electron-Phonon Coupling

TL;DR

This paper introduces a many-body $GW$ perturbation theory approach to accurately account for electron correlation effects in the long-range Fr"ohlich electron-phonon coupling, improving upon existing semiclassical methods.

Contribution

It derives and implements the $GW$ self-energy correction to the Fr"ohlich interaction, revealing its importance for precise electron-phonon property calculations.

Findings

Electron correlation effects significantly influence Fr"ohlich coupling.

The $GW$ correction alters electron linewidth and polaron formation predictions.

The approach improves the accuracy of electron-phonon interaction modeling.

Abstract

In compound semiconductors and insulators, the polar electron-phonon coupling diverges at long range, known as the Fr\"ohlich interaction. Modern first-principles electron-phonon calculations treat the Fr\"ohlich interaction in a semiclassical electrostatic formalism based on density-functional perturbation theory. Here, using many-body $GW$ perturbation theory, we reveal important electron correlation effects in the Fr\"ohlich-type electron-phonon coupling, which are missed by the prevailing approaches. Going beyond the electrostatic treatment, we derive and implement the $GW$ self-energy contribution to the long-range polar electron-phonon coupling, and demonstrate its critical role and nontrivial behaviors in properties such as electron linewidth and polaron formation. Our work establishes the many-body generalization of the Fr\"ohlich interaction that is essential for accurate electron-phonon calculations at the full $GW$ level combined with Wannier interpolation techniques.