Superhard monoclinic polymorph of carbon

Quan Li, Yanming Ma, Artem R. Oganov, Hongbo Wang, Hui Wang, Ying Xu, Tian Cui, Ho Kwang Mao, Guangtian Zou

Research output: Contribution to journalArticlepeer-review

481 Citations (Scopus)


We report a novel phase of carbon possessing a monoclinic C2/m structure (8atoms/cell) identified using an ab initio evolutionary structural search. This polymorph, which we call M-carbon, is related to the (2×1) reconstruction of the (111) surface of diamond and can also be viewed as a distorted (through sliding and buckling of the sheets) form of graphite. It is stable over cold-compressed graphite above 13.4 GPa. The simulated x-ray diffraction pattern and near K-edge spectroscopy are in satisfactory agreement with the experimental data on overcompressed graphite. The hardness and bulk modulus of this new carbon polymorph are calculated to be 83.1 and 431.2 GPa, respectively, which are comparable to those of diamond.

Original languageEnglish
Article number175506
JournalPhysical Review Letters
Issue number17
Publication statusPublished - 29 Apr 2009
Externally publishedYes


Dive into the research topics of 'Superhard monoclinic polymorph of carbon'. Together they form a unique fingerprint.

Cite this