Abstract
Compressing glassy carbon above 40 GPa, we have observed a new carbon allotrope with a fully -bonded amorphous structure and diamondlike strength. Synchrotron x-ray Raman spectroscopy revealed a continuous pressure-induced -to- bonding change, while x-ray diffraction confirmed the perseverance of noncrystallinity. The transition was reversible upon releasing pressure. Used as an indenter, the glassy carbon ball demonstrated exceptional strength by reaching 130 GPa with a confining pressure of 60 GPa. Such an extremely large stress difference of has never been observed in any material besides diamond, indicating the high hardness of this high-pressure carbon allotrope.
- Received 14 June 2011
DOI:https://doi.org/10.1103/PhysRevLett.107.175504
© 2011 American Physical Society