Researchers develop algorithm to predict new superhard crystals
An example of superhard structures of carbon found in the calculations.
(PhysOrg.com) -- Stony Brook University researchers, Artem R. Oganov, Professor of Geosciences and Physics and Dr. Andriy O. Lyakhov, Research Fellow, have developed an algorithm capable of predicting new superhard materials. The findings of their work have just been published in a paper entitled “Evolutionary search for superhard materials: Methodology and applications to forms of carbon and TiO2,” in the current online edition of Physical Review B.
Superhard materials, used in many scientific and technological applications (for example as abrasive coatings in cutting and drilling tools), are a relatively small class of compounds. The most famous and widely used of these are diamond and cubic boron nitride. However, both of them are unstable at high temperatures, which limit their applicability. Therefore, the search for new superhard compounds is of great interest. Despite numerous efforts, progress has been slow. “The traditional trial-and-error approach to search for new materials usually involves a lot of pain and little gain,” explained Prof. Oganov.
Dr. Lyakhov and Prof. Oganov propose to use supercomputers in the search for new superhard materials. Scientists developed a special hybrid evolutionary algorithm, and tested it on a few promising systems, such as carbon and carbon nitride (which many scientists believe to be able to surpass the diamond by hardness). The results show the power of this algorithm and confirm that diamond is the hardest form of carbon and, so far, the hardest material. As a byproduct of the calculations, a set of novel superhard carbon structures was obtained – these are only marginally softer than diamond. It was also shown that carbon nitride cannot be harder than diamond.
Another area where the algorithm can be used is the validation of controversial experimental data. Researchers give an example by dethroning TiO2 as the hardest known oxide. The suggestion that a high-pressure form of TiO2 is the hardest oxide was made by Swedish researchers in a highly-cited paper published in 2001 in Nature. However, calculations show that all possible forms of TiO2 are much softer than common corundum, Al2O3, and therefore the experimental data from 2001 has to be reconsidered. The latest experiments done at Yale University and the University of Tokyo point in the same direction. In the near future, scientists plan to apply their algorithm to promising systems, such as boron-carbon-oxygen compounds, to search for new superhard materials.
The value of this work goes well beyond the field of superhard materials. The optimization of hardness is a successful proof-of-principle example, which opens the way for a novel computational technique. “A new era in material design and discovery is about to begin,” said Prof. Oganov. “New materials with desired properties will be routinely discovered using supercomputers, instead of the expensive trial-and-error method that is used today.”
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Sep 14, 2011
Rank: 1.3 / 5 (6)
huh?!?
Since when do computer models and "calculations" hold more weight than experimental evidence?
A real world experiment is invalidated because a computer model doesn't support it?!? REALLY!?!
What the hell is this?
Have these people lost their minds?
Or is this article just that poorly written?
Sep 14, 2011
Rank: 3 / 5 (6)
Sep 14, 2011
Rank: 3.5 / 5 (6)
Richard Feynman: "It doesn't matter how beautiful your theory is, it doesn't matter how smart you are. If it doesn't agree with experiment, it's wrong".
Rutile Mohs hardness is 6.25, corundum 9.0 by Wolfram Alpha.
Did I miss something? Every kid knows, the rutile is way softer, than the corundum.
Why not to respect Feynman the scientist, after then?
Sep 14, 2011
Rank: 5 / 5 (1)
Many scientists don't even agree with each other.
Why not respect every argument which presents a valid point.
It's equally valid that this article poorly states the situation as well.
... and so forth.
Sep 14, 2011
Rank: not rated yet
Sep 14, 2011
Rank: 2.6 / 5 (5)
You conduct any experiments lately jigga/alizee/zephir? Cooking word soup doesnt count.Yes.
Sep 14, 2011
Rank: 3.7 / 5 (3)
"The latest experiments done at Yale University and the University of Tokyo point in the same direction."
Which is exactly what they were referring to when they said:
"Another area where the algorithm can be used is the validation of controversial experimental data."
Maybe you should read better.
Sep 14, 2011
Rank: 5 / 5 (1)
Sep 15, 2011
Rank: 3 / 5 (2)
Sep 15, 2011
Rank: not rated yet
"[...[ Lonsdaleite is simulated to be 58% harder than diamond on the <100> face and to resist indentation pressures of 152 GPa, whereas diamond would break at 97 GPa.[11] This is still below IIa diamond's <111> tip hardness of 162 GPa."
So maybe diamond is still the hardest material yet?
Sep 15, 2011
Rank: not rated yet
Sort of..
http://en.wikiped..._nanorod
Sep 15, 2011
Rank: 5 / 5 (1)
@Nanobanano
the article stated:
and the VERY NEXT SENTENCE STATES:
come on now guys --
Sep 17, 2011
Rank: not rated yet
Good point, but the thrust here is that -by their calculations- ALL forms of TiO2 are softer than diamond, not just Rutile. Besides, Rutile is far more useful for its thermal properties than its relative hardness.
Still, you were right on the money with the Feynman quote. Too bad he wasn't around when the Titanic was being designed.