Amorphous diamond: A high-pressure superhard carbon allotrope

Compressing glassy carbon above 40 GPa, we have observed a new carbon allotrope with a fully sp³-bonded amorphous structure and diamondlike strength. Synchrotron x-ray Raman spectroscopy revealed a continuous pressure-induced sp²-to-sp³ bonding change, while x-ray diffraction confirmed the persevera...

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Bibliographic Details
Published in:Physical review letters 2011-01, Vol.107 (17)
Main Authors: Lin, Yu, Zhang, Li, Mao, Ho Kwang, Chow, Paul, Xiao, Yuming, Baldini, Maria, Shu, Jinfu, Mao, Wendy L.
Format: Article
Language:English
Subjects:
catalysis (heterogeneous), solar (photovoltaic), phonons, thermoelectric, energy storage (including batteries and capacitors), hydrogen and fuel cells, superconductivity, charge transport, mesostructured materials, materials and chemistry by design, synthesis (novel materials)
MATERIALS SCIENCE
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Summary:Compressing glassy carbon above 40 GPa, we have observed a new carbon allotrope with a fully sp³-bonded amorphous structure and diamondlike strength. Synchrotron x-ray Raman spectroscopy revealed a continuous pressure-induced sp²-to-sp³ 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.
ISSN:0031-9007
1079-7114
DOI:10.1103/PhysRevLett.107.175504