Quasicrystals, an unusual atomic structural form that falls between crystal and glass, may be the most stable form of matter, despite the fact that this unusual arrangement of atoms was once considered impossible by scientists.
According to University of Michigan researchers in a new study, what makes these materials so unique is that the atoms are arranged in lattices similar to those found in crystals. Yet unlike crystals, these lattices do not repeat.
The new work relied on simulations that demonstrated how, despite quasicrystals featuring irregular patterns similar to those found in glass caused by rapid heating and cooling, these unique materials are fundamentally stable.
The Enigma of Quasicrystals
“We need to know how to arrange atoms into specific structures if we want to design materials with desired properties,” said co-author Wenhao Sun, the new study’s corresponding author and a University of Michigan Dow Early Career Assistant Professor of Materials Science and Engineering. “Quasicrystals have forced us to rethink how and why certain materials can form. Until our study, it was unclear to scientists why they existed.”
Israeli scientist Daniel Shechtman was the first to describe quasicrystals in 1984, a discovery that seemed to defy known physics. He conceived of the arrangement when he observed that the structure of certain metals, such as aluminum and manganese, resembled a cluster of many 20-sided dice joined at their faces. From these metallic arrangements, Shechtman envisioned a five-fold symmetry, where a structure would be identical from five different views.
When Shechtman proposed the idea, scientists believed that crystal lattices must repeat in all directions, making the five-fold symmetry Shechtman suggested an impossibility. However, in the years following Shechtman’s description of quasicrystals, such materials were produced both synthetically in laboratories and discovered to occur naturally in billion-year-old meteorites. With his work validated, Shechtman was eventually awarded the Nobel Prize in Chemistry in 2011.
Hellbound and Down 