Electron-phonon bound state in graphene

TL;DR

This paper investigates the electron-phonon interaction in graphene near the phonon emission threshold, revealing a bound state and showing that vertex corrections significantly enhance the electron-phonon coupling, which can be experimentally observed.

Contribution

It introduces a new dispersion equation describing an electron-phonon bound state in graphene and demonstrates the impact of vertex corrections on binding energy.

Findings

Discovery of an electron-phonon bound state in graphene.

Vertex corrections significantly increase the binding energy.

Enhanced electron-phonon coupling measurable via spectroscopy.

Abstract

The fine structure of the Dirac energy spectrum in graphene induced by electron-optical phonon coupling is investigated in the portion of the spectrum near the phonon emission threshold. The derived new dispersion equation in the immediate neighborhood below the phonon threshold corresponds to an electron-phonon bound state. We find that the singular vertex corrections beyond perturbation theory increase strongly the electron-phonon binding energy. The predicted enhancement of the effective electron-phonon coupling can be measured using angle-resolved spectroscopy.