Cubic C20: An intrinsic superconducting carbon allotrope

Abstract

Abstract Finding intrinsic carbon superconductors is an interesting topic. Based on density-functional first-principles calculations, we first study the phonon-mediated superconductivity in a cubic metallic carbon allotrope, namely sc-C20, which has been synthesized in an experiment. Electron–phonon coupling is accurately computed with the Wannier interpolation method. By solving the Eliashberg equations, we predict that sc-C20 is an intrinsic carbon superconductor, without introducing any guest atoms or doping, whose transition temperature is determined to be about 24 K. Our findings enrich the family of carbon-based superconductors.