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.”
| Newswise Science News
Argon is not the 'dope' for metallic hydrogen
24.03.2017 | Carnegie Institution for Science
Researchers make flexible glass for tiny medical devices
24.03.2017 | Brigham Young University
Astronomers from Bonn and Tautenburg in Thuringia (Germany) used the 100-m radio telescope at Effelsberg to observe several galaxy clusters. At the edges of these large accumulations of dark matter, stellar systems (galaxies), hot gas, and charged particles, they found magnetic fields that are exceptionally ordered over distances of many million light years. This makes them the most extended magnetic fields in the universe known so far.
The results will be published on March 22 in the journal „Astronomy & Astrophysics“.
Galaxy clusters are the largest gravitationally bound structures in the universe. With a typical extent of about 10 million light years, i.e. 100 times the...
Researchers at the Goethe University Frankfurt, together with partners from the University of Tübingen in Germany and Queen Mary University as well as Francis Crick Institute from London (UK) have developed a novel technology to decipher the secret ubiquitin code.
Ubiquitin is a small protein that can be linked to other cellular proteins, thereby controlling and modulating their functions. The attachment occurs in many...
In the eternal search for next generation high-efficiency solar cells and LEDs, scientists at Los Alamos National Laboratory and their partners are creating...
Silicon nanosheets are thin, two-dimensional layers with exceptional optoelectronic properties very similar to those of graphene. Albeit, the nanosheets are less stable. Now researchers at the Technical University of Munich (TUM) have, for the first time ever, produced a composite material combining silicon nanosheets and a polymer that is both UV-resistant and easy to process. This brings the scientists a significant step closer to industrial applications like flexible displays and photosensors.
Silicon nanosheets are thin, two-dimensional layers with exceptional optoelectronic properties very similar to those of graphene. Albeit, the nanosheets are...
Enzymes behave differently in a test tube compared with the molecular scrum of a living cell. Chemists from the University of Basel have now been able to simulate these confined natural conditions in artificial vesicles for the first time. As reported in the academic journal Small, the results are offering better insight into the development of nanoreactors and artificial organelles.
Enzymes behave differently in a test tube compared with the molecular scrum of a living cell. Chemists from the University of Basel have now been able to...
20.03.2017 | Event News
14.03.2017 | Event News
07.03.2017 | Event News
24.03.2017 | Materials Sciences
24.03.2017 | Physics and Astronomy
24.03.2017 | Physics and Astronomy