Web Date: October 7, 2011
Nobel Prize In Chemistry
For the discovery of a new class of materials, known as quasicrystals, Dan Shechtman, a professor of materials science at Technion-Israel Institute of Technology, has been awarded the 2011 Nobel Prize in Chemistry. His pathbreaking work on crystallinity, greeted initially with derision and skepticism, came to upend basic notions in science about the atomic structure of matter.
The honor comes with roughly $1.5 million in prize money.
While examining aluminum alloys in an electron microscope in 1982, Shechtman recorded diffraction patterns with 10-fold rotational symmetries—a condition that conventional wisdom in the field of crystallography held as impossible. Unlike ordinary crystals, the materials that Shechtman was studying lacked periodicity, meaning their atomic structure could not be depicted by a geometric pattern of atoms that repeats in three dimensions at fixed intervals. Nonetheless, they were ordered crystals—sort of.
Shechtman showed that these specimens were oddly ordered materials, which later came to be known as quasicrystals. The class of materials includes a large number of multicomponent alloys that often exhibit five- or 10-fold rotational symmetry, a condition that’s forbidden in conventional crystallography. The very definition of crystallinity included periodicity of the crystal structure. His work showing that this is not always the case redefined crystallinity.
Ever since Shechtman’s discovery, quasicrystals have sparked debate over atomic structure, stability, and other basic science issues. For years, he struggled to convince the scientific world that these structures were real and not the result of crystallography artifacts, such as crystal twinning, or misinterpretation of microscopy results.
Orderly: An icosahedral Yb-Cd quasicrystal is composed of an aperiodic ordered arrangement of YbCd clusters (yellow and blue spheres at the vertices of the polyhedra). Courtesy of Cesar Pay Gómez
Orderly An icosahedral Yb-Cd quasicrystal is composed of an aperiodic ordered arrangement of YbCd clusters (yellow and blue spheres at the vertices of the polyhedra).
Shechtman, 70, who also holds appointments at Iowa State University and Ames Laboratory, told C&EN in 1999 that when he began reporting his findings at meetings, colleagues handed him textbooks and told him that if he studied them, he would realize his claims were impossible. He also pointed out that two-time Nobel-prize winner Linus Pauling denounced the quasicrystal concept in various scientific forums in demeaning tones. But in time, many quasicrystals were observed by other researchers, including quasicrystals based on alloys of aluminum, copper, and iron and of ytterbium and cadmium.
As a result of their useful thermal and mechanical properties, quasicrystals have played central roles in a number of commercial applications, including stick- and scratch-resistant coatings for high-end cookware and hardeners for steel used in electric razors and other tools. Quasicrystals also continue to be the subject of basic studies.
“This is really wonderful news for me and my colleagues,” Shechtman said in a telephone interview with Nobelprize.org.
Longtime quasicrystals specialist Patricia A. Thiel, a professor at Iowa State and staff researcher at Ames Lab, describes her reaction this way: “I am so excited about this news—I’m high as a kite.” She adds that “Danny’s scientific achievement—his discovery of quasicrystals—is so deserving of this award.”
American Chemical Society president Nancy B. Jackson comments that “for a scientist there can hardly be anything more exciting than having definitive evidence for a discovery that changes a scientific paradigm.” She adds that “great people like Dr. Shechtman inspire us all with their contributions to science and humanity.”
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