Doping graphene near the 1/4 filling to shift the extended flat band and van Hove singularity below EF has been highly desirable. Here we report the experimental observation of an extended flat band below EF in Li-intercalated graphene. Strong electron-phonon interaction is clearly identified by notable kinks in the band dispersion. Moreover, the evolution of the band structure upon Li intercalation shows that the extended flat band and the Kekul\'e order emerge simultaneously. Our work provides opportunities for investigating flat band related instabilities and its interplay with the Kekul\'e order
@article{arxiv.2108.07254,
title = {Coexistence of extended flat band and Kekul\'e order in Li-intercalated graphene},
author = {Changhua Bao and Hongyun Zhang and Xi Wu and Shaohua Zhou and Qian Li and Pu Yu and Jia Li and Wenhui Duan and Shuyun Zhou},
journal= {arXiv preprint arXiv:2108.07254},
year = {2022}
}