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 ($\ensuremath{\sim}4\ifmmode\times\else\texttimes\fi{}{10}^{14}\text{ }\text{ }{\mathrm{cm}}^{\ensuremath{-}2}$) and strain ($\ensuremath{\sim}16%$) levels, the superconducting critical temperature ${T}_{c}$ is estimated to be as high as $\ensuremath{\sim}30\text{ }\text{ }\mathrm{K}$, the highest for a single-element material above the liquid hydrogen temperature.