Scientists defy the laws of nature by creating quasicrystals, an innovation that won a Nobel Prize in 2011.
In 1982, Dan Shechtman, a materials scientist at the Israel Institute of Technology in Haifa, discovered quasicrystals in a synthetic material. This discovery won him the Nobel Prize in chemistry, which was awarded to him in October of last year.
Quasicrystals are not like most crystals in nature such as diamonds, sugar and salt. Most crystals are symmetrical and have the same orientation throughout the entire crystal. Rotating the crystal structure of these more common materials ninety degrees will appear identical to the way it looked before rotation.
A ninety-degree rotation of a quasicrystal will not have the same affect. The patterns in quasicrystals do not repeat, so it does not show translational symmetry.
DEFYING THE NORM
Schechtman created the first quasicrystals by melting materials under high pressure, and then cooling them quickly in a process known as quenching, explains Nature Journal of Science. He preformed this process on an aluminum-manganese alloy and it formed a pattern that seemed to defy the traditional symmetry seen in more prevalent crystals.
When he looked in the microscope, he saw the pattern had symmetry over shapes of at least five sides, which is abnormal.
His discovery has not always been so well received. During the initial period after his discovery, Schechtman received much ridicule for what was widely considered to be impossible. This atomic structure was believed to defy the laws of nature and therefore could not actually exist.
Schechtman told the Israeli newspaper Haaretz last year, “People just laughed at me.” He recalled how Linus Pauling, a two time Nobel Laureate, said, “There is no such thing as quasicrystals, only quasi-scientists.”
Schechtman was even expelled from the US research team based out of the University of Pennsylvania he was working with because of the controversy that his discovery created.
Most scientists believed that there was some alternate explanation of the crystals’ structure, such as a phenomenon known as twinning, in which two normal crystals are fused together and create the appearance of not repeatable patterns. Schechtman was dismissed as an amateur for not recognizing this.
Despite the ridicule, Schechtman stuck with his discovery. Over time, people began to see that Schechtman was actually correct.
One of the major arguments for the impossibility of quasicrystals was that they had never been found in nature. This changed in 2008 when Luca Bindi of the Museo di Storia Naturale in Firenze, Italy contacted Paul Steinhardt at Princeton University to study a rock found in eastern Russia during the late 1970s. Steinhardt and other researchers looked at the rock and found it exhibited quasicrystal structures.
Steinhardt took up this problem and began to study it furiously.
“I just grabbed the problem and held on wherever it dragged me — even across the tundra,” Steinhardt said in Nature Journal of Science.
Steinhardt spent the summer of 2010 tracing the origins of the quasicrystal. This search led him back to the Koryak Mountains in Russia where the original sample had been found back in 1970.
The story of this search is more interesting than a normal expedition though. The meteorite’s earthly origins can be traced back to the The Florence Museum, which had bought it in 1990 from private collector in Amsterdam, explains Nature Journal of Science.
The researchers found the private collector’s widow who allowed them to look through her husband’s things to find clues to where he obtained the meteorite. In a diary, they found the description of a smuggling operation in Romania.
Through this description, they were able to track down the Russian agent who had worked in the smuggling operation –V.V. Kryachko. Through him the researchers were able to find the scientists who had originally found the sample.
Kryachko informed the researchers that he had dug up the rock in 1979 in the Chukotka region of Russia. The researchers took this information and traveled to the remote region near the Bering Strait.
It turns out, the sample originated from a meteorite found in the area. The ratios of elements in the quasicrystal grain are similar to what is normally found in meteorites. This led researchers to conclude that the sample came from space and is very old.
The specific elemental structure identified in the sample is one that dates back to the origin of our solar system. If this is in fact true, then quasicrystals could be as old as 4.5 billion years. Scientists are still not sure how these crystals form in nature, and it is an area that is actively being studied.
SCIENCE “FICTION” NO MORE
Another mystery that the quasicrystals hold is their practical application. So far, they have not been used for much in the real world. They are good at taking heat and converting it into electricity, which has led researchers in the automotive industry to look for ways to utilize quasicrystals to recycle wasted heat in cars.
Quasicrystals are also being used in non-stick materials such as those found on frying pans and in LEDs. Part of the reason quasicrystals have not been used for more applications may be a French patent that is somewhat restrictive to research.
“I don’t know anything about quasicrystals, but the sound of it, I think they could be used by engineers someday,” said Haifeng Ni, a sophomore in the College of Arts and Sciences.
Despite their lack of obvious practical uses, quasicrystals have had an amazing journey to get where they are today. In just thirty years they have gone from science-fiction to fact and have earned a Nobel Prize.
“It seems like they have a lot of potential. They remind me of graphene, which scientists are still figuring out uses for,” said Jon Kolnik, a junior in the College of Engineering.
It is dangerous to dismiss quasicrystals as lacking any practical uses because their journey may not be over. The next thirty years may unlock many more exciting secrets of the quasicrystal, just as the last thirty years have.
Sonal Jain, a sophomore in CAS, said, “This reminds me of modern-day alchemy. We couldn’t figure out gold, but I guess we’re able to figure out crystals.
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