Amorphous Diamond: A High-Pressure Superhard Carbon Allotrope

Journal Article · Fri Dec 09 00:00:00 EST 2011 · Phys. Rev. Lett.

DOI:https://doi.org/10.1103/PhysRevLett.107.175504· OSTI ID:1028020

Lin, Yu; Zhang, Li; Mao, Ho-kwang; Chow, Paul; Xiao, Yuming; Baldini, Maria; Shu, Jinfu; Mao, Wendy L ^[1]

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1. 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: Argonne National Lab. (ANL), Argonne, IL (United States). Advanced Photon Source (APS)
• Sponsoring Organization: NSFNNSADOE - BASIC ENERGY SCIENCES
• OSTI ID: 1028020
• Journal Information: Phys. Rev. Lett., Vol. 107, Issue (17) ; 10, 2011; ISSN 0031-9007
• Country of Publication: United States
• Language: ENGLISH

Related Subjects

71 CLASSICAL AND QUANTUM MECHANICS
GENERAL PHYSICS
BONDING
CARBON
HARDNESS
RAMAN SPECTROSCOPY
SYNCHROTRONS
X-RAY DIFFRACTION