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 (similar to 4 x 10(14) cm(-2)) and strain ( similar to 16%) levels, the superconducting critical temperature T-c is estimated to be as high as similar to 30 K, the highest for a single-element material above the liquid hydrogen temperature.