A superhard carbon allotrope: sc-C₄₆ carbon

¹ International Laboratory for Quantum Functional Materials of Henan, and School of Physics and Engineering, Zhengzhou University - Zhengzhou 450001, China
² Beijing National Laboratory for Condensed Matter Physics, Institute of Physics, Chinese Academy of Sciences Beijing 100190, China
³ Key Laboratory for Special Functional Materials of Ministry of Education, School of Physics and Electronics, Henan University - Kaifeng 475004, China

Received: 8 August 2019
Accepted: 18 November 2019

Abstract

The structural stabilities, mechanical and electronic properties of sc-C₄₆ carbon are systematically investigated by ab initio calculations. Our calculations reveal that the Vickers hardness (91 GPa) of sc-C₄₆ carbon is comparable to that of diamond and its ideal tensile and shear strength are 93 and 72 GPa, respectively. The sc-C₄₆ 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-C₄₆ 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-C₄₆ carbon.