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­­­­Shechtman, Dan

Published onJul 30, 2021
­­­­Shechtman, Dan
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(January 24, 1941 – )

Quick Facts

Dan Shechtman is a Nobel Prize winner in Chemistry (2011), and Professor of Materials Science at Iowa State since 2004.


Source: https://www.nobelprize.org/prizes/chemistry/2011/shechtman/facts/

Dan Shechtman was born on January 24, 1941 in Tel Aviv, Israel, where his father owned a printing house. His father, and both of his maternal grandparents, were Russian immigrants. For most of his childhood, his home was a small two-room house in a suburb of Tel Aviv, where he lived with his parents and younger brother, Amos.

In elementary school, Dan became interested in microscopy and begged his teacher to bring a simple optical microscope into the classroom, which he did. Dan and the microscope became nearly inseparable—a harbinger of things to come. He spent his high school years training at Petach-Tikva, a Youth Camp, where he became an expert marksman. He then served in the military for the mandatory 2.5 years.

It was during military service that Dan met his future wife, Zipora (Zippi), who was a fellow soldier. They married and had 4 children—3 girls and 1 boy. While she and Dan started the family, Zipora also completed her Bachelor's degree in sociology, graduating in 1967. She taught in schools for children with special needs, then earned her PhD at the American University in Washington, D.C. She joined the Faculty of Education at the University of Haifa in 1984. She became widely-recognized for her research on group processes for reducing aggression and violence in children and adolescents.

After military service in Israel, Dan earned several degrees from the Technion, the Israel Institute of Technology: BSc in Mechanical Engineering in 1966, MSc in Materials Engineering in 1968, and PhD in Materials Engineering in 1972. His PhD research advisor was David Brandon, and the thesis topic was 'Deformation Mechanisms of Titanium Alloys under Alternating Stress.' It was at this stage that Dan became an excellent metallurgist and a superb electron microscopist.

After earning his doctorate, he spent 3 years as a National Research Council Postdoctoral Fellow at the Wright Patterson Air Force Base in Ohio (USA), where he carried out research on the deformation mechanisms of titanium-aluminides, working closely with Harry Lipsitt and Jake Jacobson. In 1975, he returned to the Technion as a Lecturer, and rose up the academic ranks to become a Distinguished Professor of Materials Engineering and to hold the Phillip Tobias Chair. He served as Chair of his Department from 1988 to 1990.

Throughout his career, Dan has spent a few months each year in the United States as a visiting scientist. In 2004, he accepted a partial appointment at Iowa State University as a Professor of Materials Science and Engineering, and a position as Associate of the Ames Laboratory. But it was a much earlier visiting appointment in the U.S. that led to the Nobel Prize. On April 8, 1982, he was working at the National Bureau of Standards (now known as the National Institute for Standards and Technology), when he discovered quasicrystals. It was a completely unexpected result of his project, which was a broad search for new, rapidly-quenched Al-based alloys.

Rapid quenching yields such small grains that only a microscopic probe could be used in this search. Transmission electron microscopy (TEM), in particular, was well-suited, since it provides a means to measure real-space structure and diffraction in very small, thin samples. At a certain composition of Al and Mn (Al6Mn), Dan found a diffraction pattern that was tenfold symmetric. His further experiments revealed twofold and threefold axes at specific angles relative to the tenfold—angles that could only be reconciled with icosahedral symmetry. This was revolutionary! Why?

An icosahedron contains fivefold, twofold, and threefold rotational axes. (A fivefold axis “masquerades” as tenfold in a typical diffraction experiment, and this is why Dan originally observed a tenfold pattern rather than fivefold.) A fivefold axis is, however, forbidden in a periodic crystal. At the time of Dan’s discovery, a deeply ingrained belief in the materials science community was that all crystals—all ordered solids—were periodic. Hence, order was incompatible with fivefold symmetry. For this reason, Dan’s discovery ignited a storm of controversy and criticism.

At the time, it was known that crystalline materials could twin in such a way as to generate false indications of forbidden symmetries, including fivefold symmetry. Indeed, quasicrystals had been “discovered” prior to Dan Shechtman’s work, but they were either labeled as twins, or simply as unidentified phases. But Dan—with his powerful expertise in both electron microscopy and materials science—could determine whether twinning was a possible explanation. He generated a series of dark-field images, and also performed a convergent-beam experiment. These showed that the icosahedral symmetry was not due to twinning, but rather was present on the atomic scale. He was the right scientist, in the right place at the right time.

Dan’s discovery was published in Physical Review Letters in 1984. He was one of 4 co-authors who played various important roles, but it is widely acknowledged that Shechtman is the scientist who deserves credit for the discovery, and for bringing it to the attention of the scientific community. It was certainly Shechtman who bore the brunt of public criticism. This came most intensely from Linus Pauling, famous for such public statements as ‘Rest easy, my friends. There is no such thing as quasicrystals. There are only quasi-scientists.’ But Shechtman had the remarkable tenacity to hold his ground. If he had not done so, the topic easily could have become muddled, and its resolution unclear. However, the controversy spurred the scientific community to design experiments to resolve it, and the data from these experiments eventually swung opinion in Shechtman’s favor. Indeed, quasicrystals are now incorporated into introductory textbooks. This controversy and its subsequent paradigm-shift bear all the hallmarks of a classic scientific revolution.

An active, interdisciplinary community sprang up out of Shechtman’s discovery, which stimulated new mathematics (particularly tiling and random tiling), new physics (e.g. transport, magnetism, and electronic structure), discovery of new phases, new understanding of friction on hard metallic surfaces, inroads into the art of sample growth, and new chemistry (e.g. new heterogeneous catalysts). The discovery of thermodynamically stable phases in the late 1980’s advanced the field tremendously, because it allowed large, thermally-stable samples to be prepared whose properties could be characterized. From this came the realization that quasicrystals have unusual combinations of physical properties. For instance, most of the known quasicrystals are hard, brittle, and poor thermal conductors. They also exhibit low surface energy and low friction coefficients. The quest for applications based upon these physical properties has been described in detail in a book by Dubois (cited below).

The importance of Dan Shechtman's discovery of quasicrystals has been recognized by many prizes in addition to the Nobel. A few examples are the International Award for New Materials of the American Physical Society (1987), election to the Israel Academy of Sciences (1996), the Wolf Prize in Physics (1999), election to the American National Academy of Engineering (2000), and the European Materials Research Society’s 25th Anniversary Award (2008).

Dan also has many interests outside of scientific research. For example, he devotes much time and energy to improving science education, fostering international goodwill among scientists, and encouraging entrepreneurship. He is also intensely devoted to his family.

Selected Sources

Conversations between Dan Shechtman and Pat Thiel (2004-2013).

A.-P. Tsai, “Back to the Future—An Account of the Discovery of Stable Quasicrystals.” Accounts of Chemical Research 36, 31 (2003).

C. Kittel, Introduction to Solid State Physics, Seventh Edition, John Wiley & Sons, New York (1996).

D. Shechtman, I. Blech, D. Gratias, and J.W. Cahn, “Metallic Phase with Long-Range Orientational Order and No Translational Symmetry.” Physical Review Letters 53, 1951 (1984).

I. Hargittai, "There Is No Such Animal," Struct. Chem. 22 (2011) 745-748.

I. Hargittai, “Quasicrystal Discovery: A Personal Account.” The Chemical Intelligencer, 25 (1997).

J.M. Dubois, “Useful Quasicrystals.” World Scientific, Singapore, (2005).

R. Lifshitz, D. Shechtman and S. I. Ben-Abraham, Ed.  “Quasicrystals: The Silver Jubilee, Proceedings of a Conference held in Tel Aviv, Israel, in 2007.” Philosophical Magazine 88 (2008) 1879-2351.

T.S. Kuhn, The Structure of Scientific Revolutions. The University of Chicago Press, (1996).

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