Proc. Natl Acad. Sci. USA 112, 11795–11799 (2015)

Theoretical works have predicted that decorating graphene with alkali adatoms would induce superconductivity due to the enhancement of the electron–phonon coupling. However, although some studies report experimental evidence for such an enhancement, and superconductivity is well known to arise in graphite with alkali metal atoms intercalated between the layers, its observation at the single-layer level has remained elusive. Now, Bart Ludbrook and colleagues report superconductivity in graphene decorated with lithium atoms. In particular, they observed the formation of a temperature-dependent pairing gap near the Fermi energy by using high-resolution angle-resolved photoemission spectroscopy. These results suggest that the material has a superconducting phase below 5.9 K, which is of the same order as the critical temperatures previously predicted. The next step would be the demonstration of superconductivity through transport measurements, opening up the possible use of graphene in superconducting devices.