Quasicrystal discovery defied prior knowledge of matter

This year's Nobel Prize in Chemistry went to Israeli scientist Daniel Shechtman, for his discovery of quasicrystals—much of the research for which took place took place while Shechtman was on sabbatical at Hopkins from 1981 to 1983.

For those who aren't well informed in crystallography, it's probably best to explain just what the quasicrystal is from the ground up and in the simplest terms possible. Symmetry is the key to understanding the basics of atomic structure in crystals. The classical perspective on crystals is that there are only a couple of types of symmetry available to them.

The modes of symmetry are two, three, four and six-fold, meaning that crystal symmetry corresponds to these respective dimensions (i.e. two, for two-fold). In other words, how many ‘folds' the crystal possesses indicates the number of directions and planes with ordered, periodic structure.

Crystals are normally ordered, repeating structures. Structural properties of classical crystals can be seen all the way from the atomic scale to the macroscopic view of the material.

What does it mean when the crystal is known to be ‘quasi?'

Well, consider the original laws of crystal symmetry and then think a little outside the box. What if you had a crystal that possessed non-periodic structure, but had five-fold symmetry? That is the quasicrystal. It is a crystal that possesses relatively perfect structural order, but never repeats a structural pattern.

Quasicrystals are fundamentally shaped a little like pentagons. If you draw five lines from the center of a pentagon angled at 72 degrees from one another you'll find that there is five-fold symmetry in the pentagon (and thus, the crystal) no matter which way you rotate the lines.

Periodic behavior is not seen in the structure due to the manner in which the atoms fill the space of the crystal. You cannot find repeating units no matter which direction you choose to follow.

A whole new realm of materials science study has been opened with the official recognition of Dr. Schechtman's work and his recipience of the Nobel Prize. The old-school classicists who were first at odds with the existence of quasicrystals will now have to accept them for what they are.

Previous claims of quasicrystalline behavior and Dr. Schechtman's work were dismissed and relatively ignored when they were first announced. This was due to some of the rigid beliefs in classical crystal structure. In many ways, quasicrystals were not believed to be possible.

It is another facet of the Hopkins legacy that much of this important work was done while Professor Schechtman was on sabbatical here. The work might have been back in the 80's but it's making an impact today, and will continue to influence our lives from here on out.

The range of possibilities that arise from the discovery of quasicrystals is wide, from the wiring in consumer electronics to motorized engines or even in cooking utensils and surfaces.

Quasicrystals provide relatively low electrical and thermal conductivity.

Because of these positive characteristics, make sure to keep your eyes peeled for any new technologies developed using this revolutionary research.