Amorphous Diamond: A High-Pressure Superhard Carbon Allotrope
- Stanford
Compressing glassy carbon above 40 GPa, we have observed a new carbon allotrope with a fully sp{sup 3}-bonded amorphous structure and diamondlike strength. Synchrotron x-ray Raman spectroscopy revealed a continuous pressure-induced sp{sup 2}-to-sp{sup 3} 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 >70 GPa has never been observed in any material besides diamond, indicating the high hardness of this high-pressure carbon allotrope.
- Research Organization:
- Advanced Photon Source (APS), Argonne National Laboratory (ANL), Argonne, IL (US)
- Sponsoring Organization:
- NSFNNSADOE - BASIC ENERGY SCIENCES
- OSTI ID:
- 1028020
- Journal Information:
- Phys. Rev. Lett., Journal Name: Phys. Rev. Lett. Journal Issue: (17) ; 10, 2011 Vol. 107; ISSN 0031-9007; ISSN PRLTAO
- Country of Publication:
- United States
- Language:
- ENGLISH
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