上海科技大学知识管理系统

In this study, a new orthorhombic carbon structure with Ama2 symmetry, designated as O12 carbon, has been predicted on basis of the fi rst-principles method. The thermal stability and dynamic stability of O12 carbon were evaluated and confirmed by combining ab initio molecular dynamics and phonon spectra analyses. Meanwhile, the mechanical properties of O12 carbon, compared with other superhard carbon allostrope like diamond, M-carbon, Bct-c4 and Cco-C8, have also been systematically investigated. With a bulk modulus of 351 GPa, a shear modulus of 333 GPa, and a Vickers hardness of 53 GPa, O12 carbon is identified as a superhard material of significantly technological and industrial applications. The existence of elastic anisotropy in O12 carbon has also been confirmed. The electronic band structure calculations have revealed that O12 carbon exhibits a semiconductor characteristic with a direct band gap of 2.5 eV, making it promising candidate in electronic applications. Additionally, the XRD spectra of O12 carbon were obtained to offer further insights for potential experimental observations. Our fi ndings enrich the family of carbon structure and are expected to stimulate additional experimental interest.