A novel hybrid sp-sp2 metallic carbon allotrope


In this paper, we propose a novel hybrid sp-sp2 monoclinic carbon allotrope mC12. This allotrope is a promising light metallic material, the mechanical and electronic properties of which are studied based on first-principles calculations. The structure of this new mC12 is mechanically and dynamically stable at ambient pressure and has a low equilibrium density due to its large cell volume. Furthermore, calculations of the elastic constants and moduli reveal that mC12 has a rigid mechanical property. Finally, it exhibits metallic characteristics, owing to the mixture of sp-sp2 hybrid carbon atoms.

This is a preview of subscription content, log in to check access.


  1. 1.

    H. W. Kroto, J. R. Heath, S. C. O’Brien, R. F. Curl, and R. E. Smalley, C60: Buckminsterfullerene, Nature 318, 162 (1985)

    ADS  Article  Google Scholar 

  2. 2.

    S. Iijima, Helical microtubules of graphitic carbon, Nature 354, 56 (1991)

    ADS  Article  Google Scholar 

  3. 3.

    K. S. Novoselov, A. K. Geim, S. V. Morozov, D. Jiang, Y. Zhang, S. V. Dubonos, I. V. Grigorieva, and A. A. Firsov, Electric field effect in atomically thin carbon films, Science 306, 666 (2004)

    ADS  Article  Google Scholar 

  4. 4.

    B. Winkler, C. J. Pickard, V. Milman, and G. Thimm, Systematic prediction of crystal structures, Chem. Phys. Lett. 337, 36 (2001)

    ADS  Article  Google Scholar 

  5. 5.

    M. Itoh, M. Kotani, H. Naito, T. Sunada, Y. Kawazoe, and T. Adschiri, New metallic carbon crystal, Phys. Rev. Lett. 102, 055703 (2009)

    ADS  Article  Google Scholar 

  6. 6.

    Y. Yao, J. S. Tse, J. Sun, D. D. Klug, R. Martoňák, and T. Iitaka, Comment on “new metallic carbon crystal”, Phys. Rev. Lett. 102, 229601 (2009)

    ADS  Article  Google Scholar 

  7. 7.

    X. L. Sheng, H. J. Cui, F. Ye, Q. B. Yan, Q. R. Zheng, and G. Su, Octagraphene as a versatile carbon atomic sheet for novel nanotubes, unconventional fullerenes, and hydrogen storage, J. Appl. Phys. 112, 074315 (2012)

    Google Scholar 

  8. 8.

    C. He, L. Sun, C. Zhang, and J. Zhong, Two viable three-dimensional carbon semiconductors with an entirely sp 2 configuration, Phys. Chem. Chem. Phys. 15, 680 (2013)

    Article  Google Scholar 

  9. 9.

    J. T. Wang, C. Chen, E. Wang, and Y. Kawazoe, A new carbon allotrope with six-fold helical chains in allsp 2 bonding networks, Sci. Rep. 4, 4339 (2014)

    Article  Google Scholar 

  10. 10.

    G. M. Rignanese and J. C. Charlier, Hypothetical threedimensional all-sp 2 carbon phase, Phys. Rev. B 78, 125415 (2008)

    ADS  Article  Google Scholar 

  11. 11.

    Z. L. Lv, H. L. Cui, H. Wang, X. H. Li, and G. F. Ji, Theoretical study of the elasticity, ideal strength and thermal conductivity of a pure sp 2 carbon, Diamond Relat. Mater. 71, 73 (2017)

    ADS  Article  Google Scholar 

  12. 12.

    Q. Li, Y. Ma, A. R. Oganov, H. Wang, H. Wang, Y. Xu, T. Cui, H. K. Mao, and G. Zou, Superhard monoclinic polymorph of carbon, Phys. Rev. Lett. 102, 175506 (2009)

    ADS  Article  Google Scholar 

  13. 13.

    C. He, L. Sun, C. Zhang, X. Peng, K. Zhang, and J. Zhong, new superhard carbon phases between graphite and diamond, Solid State Commun. 152, 1560 (2012)

    ADS  Article  Google Scholar 

  14. 14.

    X. L. Sheng, Q. B. Yan, F. Ye, Q. R. Zheng, and G. Su, T-carbon: A novel carbon allotrope, Phys. Rev. Lett. 106, 155703 (2011)

    ADS  Article  Google Scholar 

  15. 15.

    J. Zhang, R. Wang, X. Zhu, A. Pan, C. Han, X. Li, Z. Dan, C. Ma, W. Wang, H. Su, and C. Niu, Pseudo-topotactic conversion of carbon nanotubes to Tcarbon nanowires under picosecond laser irradiation in methanol, Nat. Commun. 8, 683 (2017)

    ADS  Article  Google Scholar 

  16. 16.

    J. T. Wang, C. Chen, and Y. Kawazoe, Lowtemperature phase transformation from graphite to sp 3 orthorhombic carbon, Phys. Rev. Lett. 106, 075501 (2011)

    ADS  Article  Google Scholar 

  17. 17.

    X. Zhang, Y. Wang, J. Lv, C. Zhu, Q. Li, M. Zhang, Q. Li, and Y. Ma, First-principles structural design of superhard materials, J. Chem. Phys. 138, 114101 (2013)

    ADS  Article  Google Scholar 

  18. 18.

    Q. Wei, M. Zhang, H. Yan, Z. Lin, and X. Zhu, Structural, electronic and mechanical properties of Immacarbon, EPL 107, 27007 (2014)

    Google Scholar 

  19. 19.

    K. Umemoto, R. M. Wentzcovitch, S. Saito, and T. Miyake, Body-centered tetragonal C4: A viable sp 3 carbon allotrope, Phys. Rev. Lett. 104, 125504 (2010)

    ADS  Article  Google Scholar 

  20. 20.

    Z. Zhao, B. Xu, X. F. Zhou, L. M. Wang, B. Wen, J. He, Z. Liu, H. T. Wang, and Y. Tian, Novel superhard carbon: C-centered orthorhombic C8, Phys. Rev. Lett. 107, 215502 (2011)

    ADS  Article  Google Scholar 

  21. 21.

    C. Y. Niu, X. Q. Wang, and J. T. Wang, K6 carbon: A metallic carbon allotrope in sp 3 bonding networks, J. Chem. Phys. 140, 054514 (2014)

    ADS  Article  Google Scholar 

  22. 22.

    Y. Cheng, R. Melnik, Y. Kawazoe, and B. Wen, Three dimensional metallic carbon from distorting sp 3-bond, Crystal. Growth. Design. 16, 1360 (2016)

    Article  Google Scholar 

  23. 23.

    J. Q. Wang, C. X. Zhao, C. Y. Niu, Q. Sun, and Y. Jia, C20-T carbon: A novel superhard sp 3 carbon allotrope with large cavities, J. Phys.: Conden. Matter 28, 475402 (2016)

    Google Scholar 

  24. 24.

    Z. Li, F. Gao, and Z. Xu, Strength, hardness, and lattice vibrations of Z-carbon and W-carbon: First-principles calculations, Phys. Rev. B 85, 144115 (2012)

    Google Scholar 

  25. 25.

    M. J. Rice, A. R. Bishop, and D. K. Campbell, Unusual soliton properties of the infinite polyyne chain, Phys. Rev. Lett. 51, 2136 (1983)

    ADS  Article  Google Scholar 

  26. 26.

    T. R. Chalifoux WA, Synthesis of polyynes to model the sp-carbon allotrope carbyne, Nat. Chem. 2, 967 (2010)

    Article  Google Scholar 

  27. 27.

    H. Hirai and K. I. Kondo, Modified phases of diamond formed under shock compression and rapid quenching, Science 253, 772 (1991)

    ADS  Article  Google Scholar 

  28. 28.

    W. L. Mao, H. k. Mao, P. J. Eng, T. P. Trainor, M. Newville, C. C. Kao, D. L. Heinz, J. Shu, Y. Meng, and R. J. Hemley, Bonding changes in compressed superhard graphite, Science 302, 425 (2003)

    ADS  Article  Google Scholar 

  29. 29.

    Y. Wang, J. E. Panzik, B. Kiefer, and K. K. Lee, Crystal structure of graphite under room-temperature compression and decompression, Sci. Rep. 2, 520 (2012)

    ADS  Article  Google Scholar 

  30. 30.

    S. Zhang, Q. Wang, X. Chen, and P. Jena, Stable threedimensional metallic carbon with interlocking hexagons, Proc. Natl. Acad. Sci. USA 110, 18809 (2013)

    ADS  Article  Google Scholar 

  31. 31.

    M. Hu, M. Ma, Z. Zhao, D. Yu, and J. He, Superhard sp 2-sp 3 hybrid carbon allotropes with tunable electronic properties, AIP Advances 6, 055020 (2016)

    ADS  Article  Google Scholar 

  32. 32.

    Y. Y. Zhang, S. Chen, H. Xiang, and X. G. Gong, Hybrid crystalline sp 2-sp 3 carbon as a high-efficiency solar cell absorber, Carbon 109, 246 (2016)

    Article  Google Scholar 

  33. 33.

    C. X. Zhao, C. Y. Niu, Z. J. Qin, X. Y. Ren, J. T. Wang, J. H. Cho, and Y. Jia, H18 carbon: A new metallic phase with sp 2-sp 3 hybridized bonding network, Sci. Rep. 6, 21879 (2016)

    ADS  Article  Google Scholar 

  34. 34.

    Y. Pan, M. Hu, M. Ma, Z. Li, Y. Gao, M. Xiong, G. Gao, Z. Zhao, Y. Tian, B. Xu, and J. He, Multithreaded conductive carbon: 1D conduction in 3D carbon, Carbon 115, 584 (2017)

    Article  Google Scholar 

  35. 35.

    Q. Wei, Q. Zhang, H. Yan, and M. Zhang, A new superhard carbon allotrope: Tetragonal C64, J. Mater. Sci. 52, 2385 (2017)

    ADS  Article  Google Scholar 

  36. 36.

    X. Wu, X. Shi, M. Yao, S. Liu, X. Yang, L. Zhu, T. Cui, and B. Liu, Superhard three-dimensional carbon with metallic conductivity, Carbon 123, 311 (2017)

    Article  Google Scholar 

  37. 37.

    P. D. Jarowski, M. D. Wodrich, C. S. Wannere, P. v. R. Schleyer, and K. N. Houk, How large is the conjugative stabilization of diynes? J. Am. Chem. Soc. 126, 15036 (2004)

    Article  Google Scholar 

  38. 38.

    H. Bu, M. Zhao, Y. Xi, X. Wang, H. Peng, C. Wang, and X. Liu, Is yne-diamond a super-hard material? EPL 100, 56003 (2012)

    ADS  Article  Google Scholar 

  39. 39.

    S. W. Cranford and M. J. Buehler, Mechanical properties of graphyne, Carbon 49, 4111 (2011)

    Article  Google Scholar 

  40. 40.

    N. Narita, S. Nagai, S. Suzuki, and K. Nakao, Electronic structure of three-dimensional graphyne, Phys. Rev. B 62, 11146 (2000)

    ADS  Article  Google Scholar 

  41. 41.

    Y. Wang, J. Lv, L. Zhu, and Y. Ma, Crystal structure prediction via particle-swarm optimization, Phys. Rev. B 82, 094116 (2010)

    ADS  Article  Google Scholar 

  42. 42.

    Y. Wang, J. Lv, L. Zhu, and Y. Ma, CALYPSO: A method for crystal structure prediction, Comput. Phys. Commun. 183, 2063 (2012)

    ADS  Article  Google Scholar 

  43. 43.

    G. Kresse and J. Furthmüller, Efficient iterative schemes for ab initio total-energy calculations using a plane-wave basis set, Phys. Rev. B 54, 11169 (1996)

    ADS  Article  Google Scholar 

  44. 44.

    W. Kohn and L. J. Sham, Self-consistent equations including exchange and correlation effects, Phys. Rev. 140, A1133 (1965)

    ADS  MathSciNet  Article  Google Scholar 

  45. 45.

    J. P. Perdew, K. Burke, and M. Ernzerhof, Generalized gradient approximation made simple, Phys. Rev. Lett. 77, 3865 (1996)

    ADS  Article  Google Scholar 

  46. 46.

    G. Kresse, D. Joubert, From ultrasoft pseudopotentials to the projector augmented-wave method, Phys. Rev. B 59, 1758 (1999)

    ADS  Article  Google Scholar 

  47. 47.

    A. Togo, F. Oba, I. Tanaka, First-principles calculations of the ferroelastic transition between rutile-type and CaCl2-type SiO2 at high pressures, Phys. Rev. B 78, 134106 (2008)

    ADS  Article  Google Scholar 

  48. 48.

    A. V. Krukau, O. A. Vydrov, A. F. Izmaylov, G. E. Scuseria, Influence of the exchange screening parameter on the performance of screened hybrid functionals, J. Chem. Phys. 125, 224106 (2006)

    ADS  Article  Google Scholar 

  49. 49.

    F. Mouhat and F. X. Coudert, Necessary and sufficient elastic stability conditions in various crystal systems, Phys. Rev. B 90, 224104 (2014)

    ADS  Article  Google Scholar 

  50. 50.

    R. Hill, The elastic behaviour of a crystalline aggregate, Proc. Phys. Soc. A 65, 349 (1952)

    ADS  Article  Google Scholar 

  51. 51.

    Q. Zhang, Q. Wei, H. Yan, Q. Fan, X. Zhu, J. Zhang, and D. Zhang, Mechanical and electronic properties of P42/mnm silicon carbides, Z. Naturforsch. A 71, 387 (2016)

    ADS  Google Scholar 

  52. 52.

    S. F. Pugh, Relations between the elastic moduli and the plastic properties of polycrystalline pure metals, Lond. Edinb. Dublin Philos. Mag. J. Sci. 45, 823 (1954)

    Article  Google Scholar 

Download references


This work was financially supported by the National Natural Science Foundation of China (Grant No. 11204007), the 111 Project (B17035), the Natural Science New Star of Science and Technologies Research Plan in Shaanxi Province of China (Grant No. 2017KJXX-53), and Education Committee Natural Science Foundation in Shaanxi Province of China (Grant No. 16JK1049). Xiao-Feng Shi is acknowledged for helpful discussions and comments on the manuscript. All the authors thank the computing facilities at the High Performance Computing Center of Xidian University.

Author information



Corresponding authors

Correspondence to Qun Wei or Mei-Guang Zhang.

Rights and permissions

Reprints and Permissions

About this article

Verify currency and authenticity via CrossMark

Cite this article

Wei, Q., Zhang, Q., Zhang, M. et al. A novel hybrid sp-sp2 metallic carbon allotrope. Front. Phys. 13, 136105 (2018). https://doi.org/10.1007/s11467-018-0787-x

Download citation


  • metallic carbon allotrope
  • first-principles calculations
  • mechanical and electronic properties

PACS numbers

  • 62.20.-x
  • 63.20.-e
  • 74.20.Pq