Dan Shechtman's Accomplishments
This year was truly a year of a challenge. Challenge of establishment, that is. The most highlighted perhaps are the ongoing variations of Occupy Wall Street movements, where for many months now, protesters are still expressing their strong dissatisfaction with the current socioeconomic paradigm. Yet another type of “protester” was awarded the Nobel Prize in Chemistry this year. Dr. Dan Shechtman is that protester, and his challenge is absolutely fascinating.
It all began on the early morning of April 8, …show more content…
1982. Dr. Shechtman was performing experiments with aluminum and magnesium alloys. After taking electron diffraction (a technique that allows one to see structural patterns of a crystal on the atomic level) of a new sample in the high-‐resolution electron microscope, he immediately noticed an unusual pattern formed by the atoms. According to the Crystallography textbooks of that time, crystals are formed when atoms arrange in repeating, ordered units with specific symmetry. For example, threefold symmetry is composed of triangular units, fourfold composed of squares and sixfold of hexagons. Such geometry allows units to pack evenly without any gaps, which would occur if fivefold or pentagon units were forming the pattern. And that is exactly what he saw, something that did not fit into the accepted definition of a crystal. The fivefold pattern in the microscope seemed ordered but certainly not regular. Meaning it was composed of pentagons arranged in what seemed to be a random way.
Immediately after sharing his discovery, Dr. Shechtman encountered heavy skepticism from his fellow scientists.
At some point, as he recalled in one interview, he was given a textbook on crystallography with a suggestion to read it. “I do not need to read it, I teach this book, I know what is in it” – he replied. But he was eventually distanced by many colleagues and brutally criticized by highly prominent chemists. Despite that, he ultimately stood by his discovery and fought for the …show more content…
truth.
After two years of hostile disbelief, Dan Shechtman finally met a person who did believe in his discovery, Ilan Blech. Together they were able to solicit another physicist, John Chan, to take a look at the newly discovered, unusual crystals. And on the November 1984, with support of a French crystallographer named, Denis Gratias, they published their work describing quasicrystals in Physical Review Letters. And five weeks later, physicists Steinhardt and Levine published a paper linking quasicrystalline structure pattern to Penrose tiling.
Penrose tiling was a decades-‐old challenge of its own, proposed by Roger Penrose in the mid
1970’s as a solution to a mathematical puzzle, asking to create a mosaic with the smallest number of pieces and with an asymmetric pattern that would not repeat itself. Gradually mathematicians were able to shrink the number of tiles from 20,000 to 6 and then just 2. Two kinds of rhombs, thin and fat, were used by Penrose to lay a beautiful, aperiodic mosaic. Even more amazingly after this puzzle was solved, it turned out that some Muslim mosques were decorated by five-‐piece aperiodic mosaics dating back to the 13th century.
After the two abovementioned publications, many crystallographers went to their labs and actually replicated Dan Shechtman’s experiment.
And sure enough, disbelievers were eventually baptized by a growing number of crystallographers who observed the same fivefold symmetry as Dan Shechtman did in April 1982. After a large enough number of chemists and physicists were convinced, The International Union of Crystallography expanded the definition of a crystal to include these newly discovered quasiperiodic crystals. And almost 17 years after the discovery, The Nobel Prize committee awarded the highest scientific honor to this determined scientist who did not give up on the truth and fought for his controversial
breakthrough.
Today however, there is another challenge, to figure out practical applications of quasicrystals.
As with any new material it will take some time to discover all the possibilities for its use, yet some have already found their way into the global market. Certain properties of quasicrystals are making them very attractive to a number of industries. For example, high hardness allows use of quasicrystalline particles as a strengthening component of steel. For example, aluminum is not very strong but rather soft, meaning it deforms and does not shatter upon impact. However, if quasicrystalline particles are incorporated into aluminum, the newly formed alloy will combine unusually high strength (hardness) while keeping some of the aluminum softness.
A very similar alloy is currently in use by Sandvik Steel as a material for surgical instrument production. That specific alloy has another very unique quality: after tempering it is hardened for up to
1,000 hours. Usually softening of a material occurs after few hours but here effective service life of the instrument is greatly prolonged, allowing manufacturing of more reliable instruments.
Another interesting but not very successful integration of quasicrystals into mass market was attempted by a French utensil company named Sitram. It was discovered that quasicrystalline surface coating exhibited similar nonstick properties as Teflon, so it was rational to substitute easily scratched, soft Teflon coating for the newly developed and much harder quasicrystalline. Despite affordability and durability of the new coating, the production of pioneering utensils was halted. It turned out that common kitchen salt chemically scrapes away the quasicrystalline coating, thus undermining the excellent scratch resistance.
More applications are still under development and one is particularly worthy of mention. For example, titanium-‐based quasicrystalline alloy (TiNOx) demonstrates high solar absorbance and low emittance. What this means is that it can absorb solar energy and transform it effectively into heat. Thomas Eisenhammer, a German scientist, reported at a conference titled: “New Horizons in Quasicrystals: Research and Applications”, that he was able to build quasicrystalline-‐based solar energy absorbers with an impressive 90% absorbance and 2.5% emittance. Such results are promising but this technology still has a long way to go. Specific optical characteristics do not surpass conventional materials; nevertheless quasicrystals possess high corrosion resistance, which makes them good candidates for further development.
At the end of a recent interview Dr. Shechtman evaluated a life lesson that he was given during his struggle for truth: “If you are a scientist and believe in your results, then fight for them and fight I did
… and [the] result was extremely good for many people including me”. And even though this particular challenge ended years before his nomination for the Nobel Prize, at the time when other chemists
started to call Shechtman’s lab with positive detections of quasicrystals, another puzzle was born almost immediately -‐ practical applications of this discovery. And another challenge has begun, picked up by many people and already fruitful.
It all began on the early morning of April 8, …show more content…
1982. Dr. Shechtman was performing experiments with aluminum and magnesium alloys. After taking electron diffraction (a technique that allows one to see structural patterns of a crystal on the atomic level) of a new sample in the high-‐resolution electron microscope, he immediately noticed an unusual pattern formed by the atoms. According to the Crystallography textbooks of that time, crystals are formed when atoms arrange in repeating, ordered units with specific symmetry. For example, threefold symmetry is composed of triangular units, fourfold composed of squares and sixfold of hexagons. Such geometry allows units to pack evenly without any gaps, which would occur if fivefold or pentagon units were forming the pattern. And that is exactly what he saw, something that did not fit into the accepted definition of a crystal. The fivefold pattern in the microscope seemed ordered but certainly not regular. Meaning it was composed of pentagons arranged in what seemed to be a random way.
Immediately after sharing his discovery, Dr. Shechtman encountered heavy skepticism from his fellow scientists.
At some point, as he recalled in one interview, he was given a textbook on crystallography with a suggestion to read it. “I do not need to read it, I teach this book, I know what is in it” – he replied. But he was eventually distanced by many colleagues and brutally criticized by highly prominent chemists. Despite that, he ultimately stood by his discovery and fought for the …show more content…
truth.
After two years of hostile disbelief, Dan Shechtman finally met a person who did believe in his discovery, Ilan Blech. Together they were able to solicit another physicist, John Chan, to take a look at the newly discovered, unusual crystals. And on the November 1984, with support of a French crystallographer named, Denis Gratias, they published their work describing quasicrystals in Physical Review Letters. And five weeks later, physicists Steinhardt and Levine published a paper linking quasicrystalline structure pattern to Penrose tiling.
Penrose tiling was a decades-‐old challenge of its own, proposed by Roger Penrose in the mid
1970’s as a solution to a mathematical puzzle, asking to create a mosaic with the smallest number of pieces and with an asymmetric pattern that would not repeat itself. Gradually mathematicians were able to shrink the number of tiles from 20,000 to 6 and then just 2. Two kinds of rhombs, thin and fat, were used by Penrose to lay a beautiful, aperiodic mosaic. Even more amazingly after this puzzle was solved, it turned out that some Muslim mosques were decorated by five-‐piece aperiodic mosaics dating back to the 13th century.
After the two abovementioned publications, many crystallographers went to their labs and actually replicated Dan Shechtman’s experiment.
And sure enough, disbelievers were eventually baptized by a growing number of crystallographers who observed the same fivefold symmetry as Dan Shechtman did in April 1982. After a large enough number of chemists and physicists were convinced, The International Union of Crystallography expanded the definition of a crystal to include these newly discovered quasiperiodic crystals. And almost 17 years after the discovery, The Nobel Prize committee awarded the highest scientific honor to this determined scientist who did not give up on the truth and fought for his controversial
breakthrough.
Today however, there is another challenge, to figure out practical applications of quasicrystals.
As with any new material it will take some time to discover all the possibilities for its use, yet some have already found their way into the global market. Certain properties of quasicrystals are making them very attractive to a number of industries. For example, high hardness allows use of quasicrystalline particles as a strengthening component of steel. For example, aluminum is not very strong but rather soft, meaning it deforms and does not shatter upon impact. However, if quasicrystalline particles are incorporated into aluminum, the newly formed alloy will combine unusually high strength (hardness) while keeping some of the aluminum softness.
A very similar alloy is currently in use by Sandvik Steel as a material for surgical instrument production. That specific alloy has another very unique quality: after tempering it is hardened for up to
1,000 hours. Usually softening of a material occurs after few hours but here effective service life of the instrument is greatly prolonged, allowing manufacturing of more reliable instruments.
Another interesting but not very successful integration of quasicrystals into mass market was attempted by a French utensil company named Sitram. It was discovered that quasicrystalline surface coating exhibited similar nonstick properties as Teflon, so it was rational to substitute easily scratched, soft Teflon coating for the newly developed and much harder quasicrystalline. Despite affordability and durability of the new coating, the production of pioneering utensils was halted. It turned out that common kitchen salt chemically scrapes away the quasicrystalline coating, thus undermining the excellent scratch resistance.
More applications are still under development and one is particularly worthy of mention. For example, titanium-‐based quasicrystalline alloy (TiNOx) demonstrates high solar absorbance and low emittance. What this means is that it can absorb solar energy and transform it effectively into heat. Thomas Eisenhammer, a German scientist, reported at a conference titled: “New Horizons in Quasicrystals: Research and Applications”, that he was able to build quasicrystalline-‐based solar energy absorbers with an impressive 90% absorbance and 2.5% emittance. Such results are promising but this technology still has a long way to go. Specific optical characteristics do not surpass conventional materials; nevertheless quasicrystals possess high corrosion resistance, which makes them good candidates for further development.
At the end of a recent interview Dr. Shechtman evaluated a life lesson that he was given during his struggle for truth: “If you are a scientist and believe in your results, then fight for them and fight I did
… and [the] result was extremely good for many people including me”. And even though this particular challenge ended years before his nomination for the Nobel Prize, at the time when other chemists
started to call Shechtman’s lab with positive detections of quasicrystals, another puzzle was born almost immediately -‐ practical applications of this discovery. And another challenge has begun, picked up by many people and already fruitful.