My personal view about Daniel Shechtman, the 2011 Nobel Prize winner in Chemistry, and an attempt to bring together the scattered information on quasicrystals and the life of Daniel Shectman.
“A good scientist is a humble scientist,” said Daniel Shechtman, the winner of Nobel Prize in Chemistry (2011).
My memories were getting re-winded to the ‘group theory’ lecture during my masters, when I peeped into the details of Nobel Prize in Chemistry this year. In the lecture, my professor concluded, “Symmetry of any molecule till now could be categorized under the 32 crystallographic point groups. Anyone who can suggest a new type of symmetry or point group will surely win a Nobel prize”. When the lecture ended, just to get rid of my thoughts, I simply made myself believe that such a discovery may be impossible. That belief remained intact even during my research work in crystallography, until the day I happened to read about “quasicrystals”. I could not digest how it is possible. However, I understood one thing, if it is real; such a discovery would be phenomenal. Now, when Daniel Shechtman received the 2011 Nobel Prize in Chemistry, I feel the words of my professor almost came true.
To know more about quasicrystals, first we need to have an outline on the structure of crystals. Crystallized materials are normally made up of “unit cells” of atoms that repeat over and over to make a single, uniform structure. Normal crystals can be described by one of the 230 space groups (space groups describe the translation and rotational symmetry elements in the structure). I will make it simple for those who do not know much about it. From earlier times, our concept, or assumption was that, in a crystal, the atoms are arranged regularly like ‘tiles’. Any substance which lacks this property was simply called ‘amorphous material’. In a crystal, if we move from one end to another in a particular path, the pattern will repeat periodically. For any type of crystal in the universe, the pattern of atoms could be categorized under a set of symmetry rules – a crystal system, or a space group.
But on April 8, 1982, when Daniel Shechtman was studying a series of alloyed metals, he found out that it has a pentagonal (5-sided shape) symmetry. But such a pattern would lack translational symmetry. It will not only break the repetition of the ‘tiles’, but also disrupt the fundamentals of crystallography. When Shechtman told the world that he found a material with pentagonal symmetry, great crystallographers of the time just laughed at him. Even the prominent scientists like Linus Pauling said that he was “talking nonsense” and “There is no such thing as quasicrystals, only quasi-scientists”. Finally, head of his research group told to go back and read the textbook. He was asked to leave the group for bringing disgrace on the team!!! They thought that such a discovery is impossible.
His battle for proving quasicrystal was not too short. He worked alone to prove his findings for two years. The finding obviously was an interesting one, and many scientists from around the world started to work on these materials. Shechtman started receiving calls from several scientists, saying ‘I have it, I have it, I have it, too!’. His co-worker John Cahn supported him, he dropped everything else and started spending full time for this research (a total of 5 years). Next year itself, the world saw 300 papers reporting this class of materials! The research became a hot topic everywhere, except in US, because of the words of Linus Pauling. Back in 1984, at Princeton, Shechtman’s paper reached the table of a scientist called Steinhardt. He also was computing the unusual ways in which atoms could pack together to form crystals! This was the beginning of a teamwork to prove the existence of quasicrystals and its explanation. The term quasicrystal originally was termed by Steinhardt. Regular patterns, which follow mathematical rules, but never repeat themselves, were found in medieval Islamic mosaics (Alhambra palace, Spain and the Darb-i Imam shrine, Iran). This was similar to the pattern in quasicrystals. Later on, Shechtman made use of Electron Microscope to directly view this pattern. He told, “Without the electron microscope, I wouldn’t have made this groundbreaking discovery, or would have been delayed several years”. The success story now reached a very nice ending with the winning of Nobel prize.
I also came across two occasions in my research life, when references served inadequate to explain the findings. First one was a Sulphur-Sulphur bond breaking and a subsequent rearrangement, losing one of the Sulphur atom. My guiding scientist told me that you can publish it, but ONLY IF you yourself can find a solid reference to it. Two years later came a very similar finding from another research group, leaving nothing new for me to publish. Still, there is yet another abnormal phenomena I observed, but explained nowhere else. May be, someone will explain it before me. I regret being in the category of scientists who couldn’t interpret the obtained quaicrystals and bow to the guts and will power of Shechtman. But there are direct evidences of PhD students often facing this type of problems. In 1979 (3 years before Shechtman), Marc van Sande, a 27-year-old doctoral student working in the Electron Microscopy for Materials Science (EMAT) group at the University of Antwerp, Belgium, had recorded electron diffraction patterns from metal alloys that showed clear evidence of quasicrystals. van Sande just filed the confusing patterns in the EMAT library close to the end of his PhD. “We were making so many new discoveries every week with the high-resolution electron microscopes that the more awkward things were set aside,” recalls van Sande. “I’m realistic about it: seeing the pattern is a long way from investigating it and publishing it.”
Counting the number of Nobel Prizes associated with crystallography, the discovery of quasicrystals stands the 26th Nobel Prize in crystallography. It still isn’t clear how atoms assemble into quasicrystal structures. But the finding was (or is) a revolution in crystallography and material science. But if one may ask “what are the applications of quasi crystals?”; then there is nothing much to say regarding its real world application – scientists are working to make use of it in products like frying pans and diesel engines etc. It is told that “Shechtman’s quasi-crystals could be used to improve the mechanical properties of engineering materials and are the basis of an entirely new branch of structural science”. However, it is reported that quasicrystals have been produced in laboratories and a Swedish company found them in one of the most durable kinds of steel, which is now used in products such as razor blades and thin needles made specifically for eye surgery. “Shechtman’s key contribution to chemistry lies in opening scientists’ eyes to the possibility of new forms of matter”, said Sven Lidin, a member of the Nobel Committee for Chemistry. Thus, in my view, Shechtman is special not only for his discovery or for being a Nobel laureate, but for the valuable lesson we have to learn from his life.
Thelander, who leads the Nobel Committee for Chemistry at academy told, “Shechtman’s discovery of quasicrystals revealed a new principle for packing of atoms and molecules” – justifying the words of my professor.
For further reading in this topic, I suggest http://www.ccp14.ac.uk/ccp/web-mirrors/weber/~weber/qc.html