Abstract
We report a novel phase of carbon possessing a monoclinic structure () identified using an ab initio evolutionary structural search. This polymorph, which we call -carbon, is related to the () 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 -edge spectroscopy are in satisfactory agreement with the experimental data [W. L. Mao et al., Science 302, 425 (2003)] 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.
- Received 30 December 2008
DOI:https://doi.org/10.1103/PhysRevLett.102.175506
©2009 American Physical Society