GROWTH OF PERFECT QUASI-CRYSTALS, FROM CURIOSITY TO REALITY

Ideal quasicrystalline form of matter is defined by an atomic structure that has a perfect orientational long range order, a non-periodic long range translational order, and a non-crystallographic point group symmetry. In view of these exotic structural properties, perhaps not so surprisingly ''quasicrystals'' were also called ''impossible crystals''. These exotic structures do exist in nature and were first discovered in 1984 in an Al-Mn alloy. This particular alloy had a grain size of several microns, and was thermodynamically metastable. In eight short years, and after the discovery of many other quasicrystalline compounds, the quasicrystalline single grain size we could grow increased from microns to a few centimeters. Today, we can grow nearly defect-free and stable two- and three-dimensional quasicrystals with macroscopic dimensions. All quasicrystals discovered to date exhibit a universal non-congruent melting property which we exploit in our crystal growth techniques. This paper briefly reviews the remarkable progress made in growing single grain quasicrystals.