Hardness of T-carbon: Density functional theory calculations
- Author(s)
- Xing-Qiu Chen, Haiyang Niu, Cesare Franchini, D. Z. Li, Yiyi Li
- Abstract
We reconsider and interpret the mechanical properties of the recently proposed allotrope of carbon, T-carbon [Sheng et al., Phys. Rev. Lett. 106, 155703 (2011)], using density functional theory in combination with different empirical hardness models. In contrast with the early estimation based on Gao et al.'s model, which attributes to T-carbon a high Vickers hardness of 61 GPa comparable to that of superhard cubic boron nitride (c-BN), we find that T-carbon is not a superhard material, since its Vickers hardness does not exceed 10 GPa. Besides providing clear evidence for the absence of superhardness in T-carbon, we discuss the physical reasons behind the failure of Gao et al.'s and Simunek and Vackar's (SV) models in predicting the hardness of T-carbon, residing in their improper treatment of the highly anisotropic distribution of quasi-sp(3)-like C-C hybrids. A possible remedy for the Gao et al. and SV models based on the concept of the superatom is suggested, which indeed yields a Vickers hardness of about 8 GPa.
- Organisation(s)
- Computational Materials Physics
- External organisation(s)
- Chinese Academy of Sciences (CAS)
- Journal
- Physical Review B
- Volume
- 84
- No. of pages
- 5
- ISSN
- 1098-0121
- DOI
- https://doi.org/10.1103/PhysRevB.84.121405
- Publication date
- 2011
- Peer reviewed
- Yes
- Austrian Fields of Science 2012
- 103018 Materials physics
- Portal url
- https://ucrisportal.univie.ac.at/en/publications/a00b62ca-b581-4945-b615-34ba2258feb4