Cubic C$_{20}$: An intrinsic superconducting carbon allotrope

TL;DR

This paper predicts that the experimentally synthesized cubic carbon allotrope sc-C20 is an intrinsic superconductor with a transition temperature of about 24 K, based on first-principles calculations of electron-phonon interactions.

Contribution

It is the first to theoretically demonstrate that the cubic carbon allotrope sc-C20 is an intrinsic superconductor without doping.

Findings

sc-C20 has a transition temperature of about 24 K

Electron-phonon coupling is significant in sc-C20

Enriches the family of carbon-based superconductors

Abstract

Finding intrinsic carbon superconductor 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-C$_{20}$, which has been synthesized in experiment. The electron-phonon coupling is accurately computed with Wannier interpolation method. By solving the Eliashberg equations, we predict that sc-C$_{20}$ 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.