Physicists found a very rare quasicrystal in a piece of a meteorite that fell in Russia. The find is so rare that this is only the third time that such material has been encountered by scientists in nature. However, the uniqueness of such crystals is not only due to their rarity. The fact is that they have such a peculiar symmetrical structure that for decades science considered their existence "impossible."
The new quasicrystal was discovered by a team of geologists led by Luca Bindi from the University of Florence (Italy). Scientists examined a piece of a meteorite that fell in the Russian village of Khatyrka in the Anadyr region of the Chukotka Autonomous Okrug of Russia five years ago and found a quasicrystal only a few micrometers in size in it.
It should be noted that this is already the third quasicrystal that was discovered in the same meteorite, which may suggest that there may be even stranger structures.
“The good news is that we have already found three different types of quasicrystals in the same meteorite. The latter has a unique chemical structure never before seen in quasicrystals,”says Paul Steinhardt of Princeton University, one of the scientists involved in the study.
"This suggests that other types of quasicrystals may be hiding in a meteorite, as in nature."
The quasicrystals themselves have a unique structure, which is characterized by symmetry forbidden by classical crystallography and the presence of long-range order. In other words, the symmetry of quasicrystals is present at all scales, up to atomic, thereby demonstrating a new structural organization of matter.
Common crystals found in the same snowflakes, diamonds and table salt are composed of atoms that form almost perfect symmetry. Polycrystals, found in most metals, rocks, ice, and amorphous solids such as glass, wax, and most plastics, tend to be more chaotic and disordered.
The presence in nature of another type of atomic structure - a strange, semi-ordered form of matter in which the displayed atomic structure has point symmetry - was proved in 1982 by Israeli physicist Dan Shechtman.
Promotional video:
When Shechtman discovered a quasicrystal in a sample of an aluminum alloy that he created in the laboratory, the scientist at first did not believe his eyes, saying to himself: "This cannot be." The scientist made his discovery in 1982. Over the next decades, he twice tried to publish the results of his work in scientific journals, but he was refused. Colleagues literally laughed at the scientist, not believing his discovery. Ultimately, Shekhtman's article was published in a very abbreviated form and co-authored with other prominent scientists. The reason for the mistrust, of course, was that for more than 200 years, quasicrystals were viewed as something extremely incredible. Their supposed unique symmetry was considered beyond the traditional rules of crystallography. Yet Shechtman won the 2011 Nobel Prize in Chemistry for his work.
It is interesting to note that physicists met with quasicrystals long before their official discovery. Scientists have mistakenly identified them as cubic crystals with a large lattice constant (the size of a crystal unit cell). The unit cell, as a rule, can be represented by different shapes, for example, rectangular, cubic, triangular or hexagonal, however, quasicrystals have a structure of aperiodic order - they have five symmetrical sides, forming pentagons, which, in turn, create icosahedral symmetry.
Patricia Thiel, a senior researcher at the US Department of Energy Ames Laboratory, gives the following example:
“Let's say you want to cover your floor with mosaic tiles. The tile has perfect straight lines. It can be rectangular, triangular, square, or hexagonal. All of these shapes can be added together. Any other simple shapes cannot be folded, because gaps and spaces will remain. Quasicrystals are like pentagonal tiles. They cannot connect like triangles and squares. However, in such a structure, the gaps are filled with atoms of other substances, resulting in, for example, these forms :
And here is an image of the structure of a newly discovered quasicrystal with fifth-order symmetry:
Despite the fact that quasicrystals are very rare in nature (at least on Earth), they are very easy to create in the laboratory. At the moment, synthetic quasicrystals are used in almost everything from the production of pans to the production of LED lamps.
When scientists studied the composition of the new quasicrystal, they confirmed that it is composed of a combination of atoms of aluminum, copper and iron, combined in pentagonal shapes, like those found, for example, on soccer balls. In nature, such a composition of quasicrystals was discovered for the first time. However, the find allows n
NIKOLAY KHIZHNYAK