A New Superhard sp3-Hybridized Carbon Allotrope with Ultrawide Direct Band Gap: Ibca-C64
A novel all-<i>sp</i><sup>3</sup>-hybridized superhard carbon allotrope, <i>Ibca</i>-C<sub>64</sub>, is proposed based on first-principles calculations combined with the RG<sup>2</sup> (space group and graph theory) structure search method. A systematic investigation of its stability, mechanical properties, and electronic structure is performed. The results indicate that the energy difference between <i>Ibca</i>-C<sub>64</sub> and diamond is only 0.295 eV/atom, suggesting its metastability. Detailed analysis of its elastic constants and phonon spectrum confirms both mechanical and dynamical stability. The <i>Ibca</i>-C<sub>64</sub> structure demonstrates exceptional mechanical performance, with a Vickers hardness of 83.9 GPa. Furthermore, it possesses a wide direct band gap of 5.58 eV, indicating that <i>Ibca</i>-C<sub>64</sub> is a superhard semiconductor material with outstanding mechanical properties.
Authors
- Qun Wei (ORCID: https://orcid.org/0000-0002-2270-4389)
- Meiguang Zhang (ORCID: https://orcid.org/0000-0001-7219-843X)
- Bing Wei (ORCID: https://orcid.org/0000-0003-4735-9195)
- Jing Luo (ORCID: https://orcid.org/0000-0002-9077-1807)
- Xinyu Wang (ORCID: https://orcid.org/0000-0002-0696-2193)
Institutions
- Xidian University (CN)
- Baoji University of Arts and Sciences (CN)
Publication Details
- Journal
- Materials
- Published
- 2025-09-15
- DOI
- https://doi.org/10.3390/ma18184316
- Primary Topic
- Boron and Carbon Nanomaterials Research
- Type
- article
- Field-Weighted Citation Impact
- 0.00
Funders
- National Natural Science Foundation of China
- Xidian University
- Natural Science Basic Research Program of Shaanxi Province