Phonon-induced linewidths of graphene electronic states

TL;DR

This paper investigates the phonon-induced linewidths of graphene's electronic states using theoretical tight-binding models and experimental ARPES data, highlighting the dominant role of optical phonons and interband scattering processes.

Contribution

It provides a combined theoretical and experimental analysis of electron-phonon interactions affecting graphene's electronic state linewidths, emphasizing the importance of specific phonon modes and interband scattering.

Findings

High-energy optical phonons dominate linewidths near the $ar{ ext{Gamma}}$ point.

Interband scattering via ZA acoustic phonons significantly broadens linewidths at larger binding energies.

Calculated linewidths agree well with recent ARPES measurements.

Abstract

The linewidths of the electronic bands originating from the electron-phonon coupling in graphene are analyzed based on model tight-binding calculations and experimental angle-resolved photoemission spectroscopy (ARPES) data. Our calculations confirm the prediction that the high-energy optical phonons provide the most essential contribution to the phonon-induced linewidth of the two upper occupied $\sigma$ bands near the $\bar{\Gamma}$-point. For larger binding energies of these bands, as well as for the $\pi$ band, we find evidence for a substantial lifetime broadening from interband scattering $\pi \rightarrow \sigma$ and $\sigma \rightarrow \pi$, respectively, driven by the out-of-plane ZA acoustic phonons. The essential features of the calculated $\sigma$ band linewidths are in agreement with recent published ARPES data [F. Mazzola et al., Phys.~Rev.~B. 95, 075430 (2017)] and of the $\pi$ band linewidth with ARPES data presented here.