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 Serendipity uncovers borophene's potential
23.02.2017 | Northwestern University

nachricht Switched-on DNA
20.02.2017 | Arizona State University

All articles from Materials Sciences >>>

The most recent press releases about innovation >>>

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

Im Focus: Breakthrough with a chain of gold atoms

In the field of nanoscience, an international team of physicists with participants from Konstanz has achieved a breakthrough in understanding heat transport

In the field of nanoscience, an international team of physicists with participants from Konstanz has achieved a breakthrough in understanding heat transport

Im Focus: DNA repair: a new letter in the cell alphabet

Results reveal how discoveries may be hidden in scientific “blind spots”

Cells need to repair damaged DNA in our genes to prevent the development of cancer and other diseases. Our cells therefore activate and send “repair-proteins”...

Im Focus: Dresdner scientists print tomorrow’s world

The Fraunhofer IWS Dresden and Technische Universität Dresden inaugurated their jointly operated Center for Additive Manufacturing Dresden (AMCD) with a festive ceremony on February 7, 2017. Scientists from various disciplines perform research on materials, additive manufacturing processes and innovative technologies, which build up components in a layer by layer process. This technology opens up new horizons for component design and combinations of functions. For example during fabrication, electrical conductors and sensors are already able to be additively manufactured into components. They provide information about stress conditions of a product during operation.

The 3D-printing technology, or additive manufacturing as it is often called, has long made the step out of scientific research laboratories into industrial...

Im Focus: Mimicking nature's cellular architectures via 3-D printing

Research offers new level of control over the structure of 3-D printed materials

Nature does amazing things with limited design materials. Grass, for example, can support its own weight, resist strong wind loads, and recover after being...

Im Focus: Three Magnetic States for Each Hole

Nanometer-scale magnetic perforated grids could create new possibilities for computing. Together with international colleagues, scientists from the Helmholtz Zentrum Dresden-Rossendorf (HZDR) have shown how a cobalt grid can be reliably programmed at room temperature. In addition they discovered that for every hole ("antidot") three magnetic states can be configured. The results have been published in the journal "Scientific Reports".

Physicist Dr. Rantej Bali from the HZDR, together with scientists from Singapore and Australia, designed a special grid structure in a thin layer of cobalt in...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

Event News

Booth and panel discussion – The Lindau Nobel Laureate Meetings at the AAAS 2017 Annual Meeting

13.02.2017 | Event News

Complex Loading versus Hidden Reserves

10.02.2017 | Event News

International Conference on Crystal Growth in Freiburg

09.02.2017 | Event News

 
Latest News

Stingless bees have their nests protected by soldiers

24.02.2017 | Life Sciences

New risk factors for anxiety disorders

24.02.2017 | Life Sciences

MWC 2017: 5G Capital Berlin

24.02.2017 | Trade Fair News

VideoLinks
B2B-VideoLinks
More VideoLinks >>>