New Superhard Form of Carbon Dents Diamond

Squeezing creates new class of material built from clusters of carbon atoms.

Diamond anvil showing dents (arrowed) after being used to squeeze this new superhard material. — Image courtesy of Carnegie Institute of Washington

The Science

Using high pressures, a new class of material has been discovered which consists of disordered clusters of carbon atoms organized with long-range periodicity.

The Impact

Carbon is a unique material that exists in many different structures, each having different properties (e.g. graphite, graphene, and diamond). This research demonstrated yet another structure that is superhard, and opens the door to a whole new class of carbon with potentially extraordinary properties.

Summary

How do you dent diamond, one of the Earth’s hardest materials? Researchers supported by the Energy Frontier Research in Extreme Environments EFRC created a new substance that can do just that. To make the new material, the researchers started with ‘buckyballs,’ soccer-ball shaped cages composed of sixty carbons, and mixed them in a liquid solvent called xylene. The molecules of xylene served to “link” the buckyballs together in a regular, crystalline pattern like beads on a string. Finally, they squeezed the mixture in a diamond anvil cell in-situ in the synchrotron beam of the Advanced Photon Source. Something extraordinary happened around 320,000 times atmospheric pressure; the buckyballs collapsed and formed disordered, amorphous clusters but the xylene molecules held fast and still tethered the amorphous pieces together in a pattern like before. The resulting, never-before-seen structure was surprisingly hard; strong enough to dent the diamond anvil. The material stayed in the same structure even after the pressure had been released, which makes it potentially useful for a variety of different devices, especially future electronics. (Excerpt from DOE-SC's "In Focus")

Contact

Lin Wang
Carnegie Institution of Washington and Jilin University}
[email protected]

Ho-kwang Mao
Director of the Energy Frontier Research in Extreme Environments (EFree) EFRC
[email protected]

Funding

DOE Office of Science, Basic Energy Sciences, Energy Frontier Research Centers (EFRC) Program; HPCAT, Advanced Photon Source (APS) with support from the Office of Science, Basic Energy Sciences and the National Science Foundation; Calculations used Oak Ridge Leadership Class Computing Facility, supported by the Office of Science, Advanced Scientific Computing Research, and university computing capabilities; National Natural Science Foundation of China and Program for New Century Excellent Talents in University (supported Jilin University research group to synthesize and characterize samples)

Publications

Wang, Lin; Liu, Bingbing ; Li, Hui; Yang, Wenge; Ding, Yang; Sinogeikin, Stanislav V.; Meng, Yue ; Liu, Zhenxian; Zeng, Xiao Cheng ; and Mao, WendyL. “Long-range ordered carbon clusters: A crystalline material with amorphous building blocks”Science, 337, 825-828 (2012). [DOI: 10.1126/science.1220522]