anything, as long as it's small

Tunable excitons in bilayer graphene

Long Ju, Lei Wang, Ting Cao, Takashi Taniguchi, Kenji Watanabe, Steven G. Louie, Farhan Rana, Jiwoong Park, James Hone, Feng Wang, Paul L. McEuen

Science 358, 907-910 (2017)