The discovery of superconductivity in CaC6 with a critical temperature (Tc) of 11.5 K reignites much interest in exploring high-temperature superconductivity in graphite intercalation compounds (GICs). Here we identify a GIC NaC4, discovered by ab initio evolutionary structure search, as a superconductor with a computed Tc of 41.2 K at 5 GPa. This value is eight times higher than that of the synthesized GIC NaC2 and possesses the highest Tc among available GICs. The remarkable superconductivity of GIC NaC4 mainly arises from the coupling of {\pi} electrons in graphene with the low-frequency vibrations involving both Na and C atoms. These findings suggest that Na-GICs may hold great promise as high-Tc superconductors.
@article{arxiv.2305.00444,
title = {Superconductivity in graphite intercalation compounds with sodium},
author = {Chun-Mei Hao and Xing Li and Artem R. Oganov and Jingyu Hou and Shicong Ding and Yanfeng Ge and Lin Wang and Xiao Dong and Hui-Tian Wang and Guochun Yang and Xiang-Feng Zhou and Yongjun Tian},
journal= {arXiv preprint arXiv:2305.00444},
year = {2023}
}