Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

Geosciences Professor Establishes Structure Of A New Superhard Form Of Carbon

28.06.2012
An international team led by Artem R. Oganov, PhD, a professor of theoretical crystallography in the Department of Geosciences at Stony Brook University, has established the structure of a new form of carbon. The results of their work, “Understanding the Nature of Superhard Graphite,” were published June 26 in Scientific Reports, a new journal of the Nature Publishing Group.

Dr. Oganov and his team used a novel computational method to demonstrate that the properties of what had previously been thought to be only a hypothetical structure of a superhard form of carbon called “M-carbon” – constructed by Oganov in 2006 – matched perfectly the experimental data on “superhard graphite.”

“Most of the known forms of carbon have a colorful story of their discovery and a multitude of real or potential revolutionary applications,” said Oganov. “Think of diamond, a record-breaking material in more than one way. Think of graphene, destined to become the material of electronics of the future. Or of fullerenes, the discovery of which has started the field of nanoscience.”

The story of yet another form of carbon started in 1963, when Aust and Drickamer compressed graphite at room temperature. High-temperature compression of graphite is known to produce diamond, but at room temperature an unknown form of carbon was produced. This new form, like diamond, was transparent and superhard - but its other properties were inconsistent with diamond or other known forms of carbon.

“The experiment itself is simple and striking: you compress black ultrasoft graphite, and then it suddenly turns into a colorless, transparent, superhard and mysterious new form of carbon – ‘superhard graphite,’” said Oganov. “The experiment was repeated several times since, and the result was the same, but no convincing structural model was produced, due to the low resolution of experimental data.”

Using his breakthrough crystal structure prediction methodology, Oganov in 2006 constructed a new low-energy superhard structure of “M-carbon.” That work resulted in a stream of scientific papers that within two years proposed different “alphabetic” structures, such as F-, O-, P-, R-, S-, T-, W-, X-, Y-, Z-carbons. “The irony was that most of these also had properties compatible with experimental observations on ‘superhard graphite.’ To discriminate between these models, higher-resolution experimental data and additional theoretical insight are required,” he said.

According to Oganov, the reason why diamond is not formed on cold compression of graphite is that the reconstruction needed to transform graphite into diamond is too large and is associated with too great an energy barrier, which can be overcome only at high temperatures, when atoms can jump far. At low temperatures, graphite chooses instead a transformation associated with the lowest activation barrier.

One could establish the structure of ‘superhard graphite’ by finding which structure has the lowest barrier of formation from graphite. To do that, Oganov, his postdoctoral associate Salah Eddine Boulfelfel, and their German colleague, Professor Stefano Leoni, of Dresden University of Technology, used a powerful simulation approach, recently adapted to solid materials, known as transition path sampling. These simulations required some of the world's most powerful supercomputers, and finally proved that "superhard graphite" is indeed identical to M-carbon, earlier predicted by Oganov.

“These calculations are technically extremely challenging, and it took us many months to perform and analyze them. Searching for the truth, you have to be prepared for any outcome, and we were ready to accept if another of the many proposed structures won the contest. But we got lucky, and our own proposal – M-carbon – won,” said Oganov.

Another result of this study is a set of detailed mechanisms of formation of several potential carbon allotropes. These could be used to engineer ways of their synthesis for potential technological applications.

“We don't know yet which applications M-carbon will find, but most forms of carbon did manage to find revolutionary applications, and this amazing material might do so as well,” said Oganov.

Please click here (http://www.youtube.com/watch?v=bm0ZmXpHCk0) for a short video by Salah Eddine Boulfelfel on the “New Carbon Allotrope at High Pressure” from the Artem Oganov Lecture Series.

| Newswise Science News
Further information:
http://www.stonybrook.edu

More articles from Materials Sciences:

nachricht Atomic 'Swiss army knife' precisely measures materials for quantum computers
07.07.2020 | National Institute of Standards and Technology (NIST)

nachricht Carbon-loving materials designed to reduce industrial emissions
06.07.2020 | DOE/Oak Ridge National Laboratory

All articles from Materials Sciences >>>

The most recent press releases about innovation >>>

Die letzten 5 Focus-News des innovations-reports im Überblick:

Im Focus: Excitation of robust materials

Kiel physics team observed extremely fast electronic changes in real time in a special material class

In physics, they are currently the subject of intensive research; in electronics, they could enable completely new functions. So-called topological materials...

Im Focus: Electrons in the fast lane

Solar cells based on perovskite compounds could soon make electricity generation from sunlight even more efficient and cheaper. The laboratory efficiency of these perovskite solar cells already exceeds that of the well-known silicon solar cells. An international team led by Stefan Weber from the Max Planck Institute for Polymer Research (MPI-P) in Mainz has found microscopic structures in perovskite crystals that can guide the charge transport in the solar cell. Clever alignment of these "electron highways" could make perovskite solar cells even more powerful.

Solar cells convert sunlight into electricity. During this process, the electrons of the material inside the cell absorb the energy of the light....

Im Focus: The lightest electromagnetic shielding material in the world

Empa researchers have succeeded in applying aerogels to microelectronics: Aerogels based on cellulose nanofibers can effectively shield electromagnetic radiation over a wide frequency range – and they are unrivalled in terms of weight.

Electric motors and electronic devices generate electromagnetic fields that sometimes have to be shielded in order not to affect neighboring electronic...

Im Focus: Gentle wall contact – the right scenario for a fusion power plant

Quasi-continuous power exhaust developed as a wall-friendly method on ASDEX Upgrade

A promising operating mode for the plasma of a future power plant has been developed at the ASDEX Upgrade fusion device at Max Planck Institute for Plasma...

Im Focus: ILA Goes Digital – Automation & Production Technology for Adaptable Aircraft Production

Live event – July 1, 2020 - 11:00 to 11:45 (CET)
"Automation in Aerospace Industry @ Fraunhofer IFAM"

The Fraunhofer Institute for Manufacturing Technology and Advanced Materials IFAM l Stade is presenting its forward-looking R&D portfolio for the first time at...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

VideoLinks
Industry & Economy
Event News

Contact Tracing Apps against COVID-19: German National Academy Leopoldina hosts international virtual panel discussion

07.07.2020 | Event News

International conference QuApps shows status quo of quantum technology

02.07.2020 | Event News

Dresden Nexus Conference 2020: Same Time, Virtual Format, Registration Opened

19.05.2020 | Event News

 
Latest News

Quick notes in the genome

07.07.2020 | Life Sciences

Limitations of Super-Resolution Microscopy Overcome

07.07.2020 | Life Sciences

Put into the right light - Reproducible and sustainable coupling reactions

07.07.2020 | Life Sciences

VideoLinks
Science & Research
Overview of more VideoLinks >>>