Quasi-Periodic Materials – Crystal Redefined

Public Lecture @ 21th Annual Meeting of the German Crystallographic Society (DGK) 2013

Foto: Technion – Israel Institute of Technology

Public Lecture of Nobel Prize Laureate Prof. Dan Shechtman

Dan Shechtman received the Nobel Prize in Chemistry in 2011 for the discovery of quasicrystals. He proved for the first time the existence of aperiodic crystalline structures in the system Al-Mn in 1982 and published his observations in 1984.

Following his PhD studies at the Technion – Israel Institute of Technology  in Haifa, which he finished in 1972, he spent three years as NRC Fellow at the Aerospace Research Laboratory at Wright Patterson Air Force Base in Ohio. Since 1975 he was a member of the department of materials engineering at the Technion in Israel. The work which made him famous originates from the time of his sabbatical at the Johns Hopkins University, Baltimore, during the years 1981–1983. Studying Al-Mn alloys in the transmission electron microscope, he observed for the first time 10-fold symmetric diffraction patterns.Until that time, it was believed that only structures consisting of 3-dimensionally periodic lattices can give rise to sharp interference patterns. These structures can possess 2-, 3-, 4- or 6-fold symmetries but never 5- or 10-fold symmetries. Since his discovery contradicted all common sense and science, it took him as long as 2 years to confirm and verify his results. Dan Shechtman showed in his work that structures with periodicity in higher dimensional space really exist in nature and yield indeed their own characteristic footprints in diffraction patterns.

In 1984 Dan Shechtman returned as Associate Professor to the Department of Materials Engineering at Technion and became Full Professor in 1986. Since 1998 he is Distinguished Professor of the Philip Tobias Chair for Materials Science at the Technion.