The world’s most complex crystal never repeats

[etienne_marais]

The world’s most complex crystal never repeats

The most complicated crystal structure ever produced in a computer simulation is a lesson in how complexity can emerge from simple rules.

The “icosahedral quasicrystal” looks ordered to the eye, but has no repeating pattern. At the same time, it’s symmetric when rotated, similar to a soccer ball with five-fold and six-fold patches.

Researchers say this property, called “icosahedral symmetry,” is frequently found on small scales around a single point, like in virus shells or buckyballs—molecules of 60 carbon atoms.

But it is forbidden in a conventional crystal.

Even though the end product shows long-range order, the particles only interacted with those up to three particle-distances away. When the researchers looked closer, they found that the Golden Ratio governed those interactions.

“These findings help answer fundamental questions that are important in all of nature: how do you get really complex arrangements of atoms and molecules from essentially local information? This is a beautiful example of something incredibly rich in structure emerging from very simple rules,” Glotzer says.

http://www.geologyin.com/2016/11/the-worlds-most-complex-crystal-never.html