Nobel Prize in Chemistry 2011: Dan Shechtman and the discovery of quasicrystals
January 9, 2012 - 10:00am
Marcus Nanotech Conf.
The Nobel prize in Chemistry 2011 was awarded to Dan Shechtman for his “Discovery of Quasicrystals”. This discovery published in a seminal paper in November 1984  lead to the re-definition of crystalline structures. What Shechtman has observed is a long-range icosahedral symmetry in an aluminum –based alloy. Five-fold symmetry is in clear violation of periodic order, which was the paramount dogma of crystallography. To reconcile a discrete diffraction diagram and forbidden symmetry has required, not without resistance from the community, to reconsider what was known for centuries about crystalline order and to realize that what Shechtman had observed was a new type of atomic structure, which is non periodic yet perfectly ordered.
Quasicrystals of various symmetries have been now observed in a number of compounds, man-made and natural. Quasicrystals is a new cross-disciplinary field of study, reaching to chemistry, physics and mathematics. I will mainly discuss the structure of quasicrystals, the aesthetics of their order based on the golden mean. I will touch upon fundamental questions like what becomes of properties, for instance electronic transport, for quasiperiodic rather than the usual periodic ordered structures.
 Dan Shechtman, I. Blech, D. Gratias, J. Cahn, Phys. Rev. Lett. 53, 1951 (1984).