First-principles calculations on the effect of doping and biaxial tensile strain on electron-phonon coupling in graphene.

Graphene has exhibited a wealth of fascinating properties, but is also known not to be a superconductor. Remarkably, we show that graphene can be made a conventional Bardeen-Cooper-Schrieffer superconductor by the combined effect of charge doping and tensile strain. While the effect of doping obviously enlarges the Fermi surface, the effect of strain profoundly increases the electron-phonon coupling. At the experimental accessible doping (~4×10(14) cm(-2)) and strain (~16%) levels, the superconducting critical temperature T(c) is estimated to be as high as ~30 K, the highest for a single-element material above the liquid hydrogen temperature.