The importance of phonons in the strong correlation phenomena observed in twisted bilayer graphene (TBG) at the so-called magic-angle is under debate. Here we apply gate-dependent micro-Raman spectroscopy to monitor the G band linewidth in TBG devices of twist angles θ=0∘, ∼1.1∘ (magic-angle) and ∼7∘ (large angle). The results show a broad and p/n-asymmetric doping behavior at the magic-angle, in clear contrast to the behavior observed in twist angles above and below. Atomistic modeling reproduces the experimental observations, revealing how the unique electronic structure of magic-angle TBGs influences the electron-phonon coupling and, consequently, the G band linewidth. Our findings indicate a connection between electron-phonon coupling and experimental observations of strongly correlated phenomena in magic-angle TBG.
@article{arxiv.2110.14916,
title = {Electron-phonon coupling in a magic-angle twisted-bilayer graphene device},
author = {Andreij C. Gadelha and Viet-Hung Nguyen and Eliel G. Neto and Fabiano Santana and Markus B. Raschke and Michael Lamparski and Vincent Meunier and Jean-Christophe Charlier and Ado Jorio},
journal= {arXiv preprint arXiv:2110.14916},
year = {2022}
}