A superhard carbon allotrope: sc-C46 carbon

The structural stabilities, mechanical and electronic properties of sc-C-46 carbon are systematically investigated by ab initio calculations. Our calculations reveal that the Vickers hardness (91 GPa) of sc-C-46 carbon is comparable to that of diamond and its ideal tensile and shear strength are 93 and 72 GPa, respectively. The sc-C-46 carbon is unveiled to be an insulator with a quasi-direct band gap of 5.11 eV. By simulating X-ray diffraction patterns, we propose that sc-C-46 carbon may be one of the unidentified carbon phases in the detonation and chimney soot. These findings provide a solid footing for further exploration of the interesting properties and practical applications of sc-C-46 carbon. Copyright (C) EPLA, 2020