Tunable broadband superradiance near a graphene/hyperbolic metamaterial/graphene sandwich structureYing Zhou, Hongqian Mu, Tongbiao Wang, Tianbao Yu and Qinghua LiaoEur. Phys. J. B, 95 11 (2022) 193DOI: https://doi.org/10.1140/epjb/s10051-022-00456-0