image: Meeting at the National Bureau of Standards (now known as the National Institute of Standards and Technology, or NIST) in 1985 just months after shaking the foundations of materials science with publication of his discovery of quasicrystals, Daniel Shechtman, winner of the 2011 Nobel Prize in Chemistry, discusses the material’s surprising atomic structure with collaborators. From left to right are Shechtman; Frank Biancaniello, NIST; Denis Gratias, National Science Research Center, France; John Cahn, NIST; Leonid Bendersky, Johns Hopkins University (now at NIST); and Robert Schaefer, NIST. view more
Credit: H. Mark Helfer/NIST
National Institute of Standards and Technology (NIST) colleagues of Daniel Shechtman have joined others in the scientific community in congratulating him on winning the 2011 Nobel Prize in Chemistry. Shechtman made his astonishing discovery of a quasicrystal—an arrangement of atoms thought to be forbidden by nature—while working as a guest researcher at NIST (then known as the National Bureau of Standards) in 1982.
Shechtman is currently a professor at the Israel Institute of Technology (Technion).
"We are thrilled that Dr. Shechtman's pioneering work has been recognized with this well-deserved prize," said NIST Director Patrick Gallagher. "This discovery completely changed the thinking of scientists about unusual arrangements of atoms within crystals and ultimately helped them to fabricate a wide range of new types of materials."
The discovery, which launched an entirely new and, since, highly productive branch of materials science was so surprising that even his collaborators were a bit wary. NIST's John Cahn, a National Medal of Science winner in 1998, thought the peculiar arrangement in the material—a rapidly cooled combination of aluminum and manganese, suggested that it was due to "twinning," a flaw occasionally encountered in samples of crystalline materials.
"My initial reaction was, 'Go away, Danny. These are twins and that's not terribly interesting," recalled Cahn, a co-author on the 1984 journal article * that reported the discovery.
However, Shechtman's scrutiny of the ribbon-like sample under a transmission electron microscope and by means of X-ray diffraction eliminated twinning as a cause of the extraordinary atomic structure and pointed in the direction of a material with five-fold symmetry. The breakthrough was, in Cahn's words "pure serendipity," a paradigm-breaking result spawned by Shechtman's research and persistence. Several NIST colleagues, who were focusing on the thermodynamics of rapidly solidified metal alloys, assisted him in the research.
Since the early 1800s, the laws governing the shape and form of crystal materials were well established. And since the early 1900s, X-ray diffraction studies enabled scientists to determine the precise organization of atoms within crystals—a symmetrical pattern of a continually repeating arrangement of atoms, called a unit cell. For more than a century, scientists believed that they had documented all the allowed arrangements of atoms in crystals—exactly 230 groupings in three dimensions.
Then came Shechtman's seemingly outrageous discovery of a quasicrystal—a material that neither had the periodic symmetry of crystals nor the disordered or amorphous structure of other materials, such as glass. It was an "almost crystal" an aperiodic object that yielded diffraction patterns just like crystals, which are periodic objects with a regularly repeating internal structure.
Thanks to their novel structure, quasicrystals have properties that have proved desirable for a variety of products and applications. Examples include coatings in high-tech cookware that have non-stick, extremely durable surfaces. Quasicrystals also are used in components for energy-saving light-emitting diodes (LED) and in heat insulation in engines.
Shechtman was on a two-year sabbatical and worked as a guest researcher at NIST from 1981 to 1983. He then returned to Technion, where he continued to pore over the diffraction pattern data that he had collected at NIST. In 1984, he returned to NIST at the invitation of Cahn, to consult further. Initial efforts to publish an article reporting five-fold symmetry were unsuccessful until November 12, 1984, when the landmark article was published in Physical Review Letters.
Besides Cahn as one of Shechtman's three co-authors, the article acknowledges other NIST contributors. It cites materials scientist Frank Biancaniello (now retired) and Camden R. Hubbard (now at Oak Ridge National Laboratory) for X-ray experiments.
During the 1980s, Shechtman continued to return to NIST to work with his collaborators. Between 1984 and 1986, NIST materials engineer William Boettinger and Shechtman were among the co-authors listed on five articles exploring aspects of quasicrystals.
* D. Shechtman, I. Blech, D. Gratias, J.W. Cahn, Metallic Phase with Long-Range Orientational Order and No Translational Symmetry. Physical Review Letters. Vol. 53, No. 20; Nov. 12, 1984.