Exclusive to the Hidan website: the chapter dealing with Prof. Dan Shechtman - impossible material, from Ishtavan Hargitay's book Drive And Curiosity

This chapter describes Prof. Dan Shechtman's journey from the discovery of the phenomenon of quasi-periodic crystals, to the convincing of the scientific world. We thank the author for agreeing to translate this chapter.

Translation: Dr. Moshe Nachmani. All rights are reserved to the original copyright holder, Prof. Ishtvan Hargitai and this text may not be used without his permission and the permission of the knowledge site.

Chapter 8
stubbornness
"impossible" material

“…people can find me quite stubborn.”
Dan Shechtman

Dan Shechtman (born in 1941) came upon a random observation, which turned into a triumphant discovery - thanks to his stubbornness and perseverance. These were important features. When Shechtman was a student, he passed an exam in crystallography with the help of the demonstration of the proof of why 5th order rotational symmetry is not possible in the world of crystals, believed to be an ancient example (system of principles) in the field of the solid state. Shechtman's discovery of the quasi-periodic crystals (quasicrystals) helped to eliminate this example. Alas, the most influential chemist of his time declared that Shechtman's discovery was a non-discovery. The journal to which Schechtman submitted the first article about his discovery rejected it saying that physicists would never be interested in this discovery. When he was eventually able to publish his paper, it spawned a snowball of publications that followed. Shechtman's discovery turned out to be important for the fields of chemistry, physics, material sciences and even for the sciences of art and design.

For a long time it was accepted that rotational symmetry of the 5th order is not possible at all in the world of crystals, where atoms and molecules make up the structure in a way that does not allow any overlap or gaps in their packing arrangement. A simple demonstration of the impossibility of order 5 symmetry in the world of crystals appears below - we can use triangles, squares and hexagons of the same size in order to cover a surface without getting overlaps or spaces, but this cannot be done if we use elaborate pentagons of the same size. Similarly, symmetries of order 7 and higher were also considered impossible.

For a long time, famous scientists and artists such as Johannes Kepler and Albrecht Dürer tried to create patterns in which elaborate pentagons cover a surface, without any success. However, the British mathematician Roger Penrose also tried it. He came from a family with unusual interests. His father, Lionel Penrose was a professor of human genetics at Oxford University and it was he who encouraged his son Roger to pursue science. Roger Penrose became not only a well-known mathematician, but also a famous writer. One of his hobbies, especially when he was present at meetings that bored him, was to scribble.

One day, the symbol on my personal letterhead caught his eye; The symbol consisted of a central pentagon which was surrounded by five other, larger pentagons. This pattern encouraged Penrose to construct a pattern in which this pattern repeats itself by drawing ever-growing pentagons. He used not only whole pentagons, but also parts of them, in order to fully cover the surface. This scribble led to an eye-catching pattern that covered the surface with elaborate pentagons, but of increasing size. This pattern was the closest, at this point in time, to the dreams of Kepler and Diirer. Penrose published his findings in an insignificant journal in the field of mathematics, but when Martin Gardner wrote about them in the scientific journal Scientific American, they became famous.

Another British scientist, crystallographer Alan McKee, was intrigued by Penrose's pattern. Crystalline structures can be tested by utilizing the diffraction phenomenon, in which X-rays, a neutron beam or an electron beam directed towards some material change their directions while obtaining characteristic patterns from which it is possible to determine what the internal structure is. McKee decided to simulate a refraction experiment based on the Penrose pattern. He reasoned that if he could produce a diffraction pattern characterized by sharp bright spots, then this would indicate that even three-dimensional structures matching Penrose's two-dimensional pattern on paper could exist. McKee was particularly alert to structures that were not included in the accepted realm of seemingly perfect crystals. He followed in the footsteps of his teacher - G. Desmond Bernal - in his attempts to expand the field of crystallography. McKee was able to produce his simulated probability experiment and warned other scientists in his lectures and papers that a 5th order rotational symmetry might exist, but one that could be missed in the face of our science's firmly established dogma of its non-existence.

I was intrigued by McKee's publications and was happy to meet him in 1981 in Ottawa during a crystallography conference. We began to correspond and he visited us in Budapest in September 1982. He gave three lectures, two of which discussed the various aspects of 5th order rotational symmetry. On this occasion I came across his warning about the possibility of solid structures with 5th order symmetry. His views sounded esoteric, but he made them sound convincing. No one in the audience, including McKee himself, knew that four months earlier the very structures that McKee had only predicted had been experimentally observed.

Unbeknownst to McKee and Penrose, Dan Schechtman was conducting experiments that were directly related to their own experiments. Shechtman was a graduate of the Technion - the Israeli Institute of Technology - and a materials scientist who researched several materials and prepared new ones with sought-after properties, including new metal alloys. He did his research at the Technion, but occasionally he stayed for varying periods of time in American research laboratories. He was not at all interested in the issue of 5th order rotational symmetry.

In 1981 Shechtman took a sabbatical year from the Technion and stayed at the US National Standards Office (NIST), near Washington. He was invited there by one of the institute's senior scientists, John Kahan, in light of the development of a new technique for studying metallic powders using an electron microscope.

Since Shechtman was interested in creating new alloys, he began to investigate the rapidly solidifying clay-iron alloys and examined the effects of composition and the conditions of their solidification on the structure and properties of these new alloys. Rapid solidification is one of the approaches that allow influencing the properties of alloys. Shechtman learned a lot about the process of rapid solidification and prepared several articles for publication, in collaboration with his colleagues from the institute. Together they prepared useful materials, but the method they developed did not become a common method. The discovery he eventually arrived at was unexpected and was a byproduct of these studies.

In some of his experiments, Shechtman wanted to compare two alloys of similar composition, one consisting of clay and iron, and the other of clay and manganese. As part of these experiments, he prepared a series of iron-manganese alloys with increasing amounts of manganese. In view of practical needs, Shechtman had to limit the manganese content to a few percent; Otherwise, the alloy becomes brittle and brittle, and consequently, useless. However, in a certain experiment Shechtman's curiosity overcame his common sense, and he continued to increase the amount of manganese in the alloys. These are the types of experiments we will read about only if they were successful; Experiments that do not succeed, disappear from the books as if they did not exist.

On April 1982, 25, Schechtman examined with his electron microscope a sample of a rapidly solidifying iron-manganese alloy that contained 10% manganese, and saw something that was completely unexpected. The diffraction pattern he recorded on the photographic plate showed signs characteristic of a packing that could be defined as arising only from a structure with rotational symmetry of order XNUMX.

He meticulously recorded in his lab notebook for plate number 1725, Hamran-25% playing the following note: "Symmetry of order 10???" He noticed ten bright spots in the studied probability pattern; And they were found at the same intervals from each other. He counted them over and over, and said to himself, in Hebrew: "There is no such animal". He had enough experience in general crystallography to understand immediately that he had discovered something extraordinary. He was not familiar with McKee's imaging experiment, much less his warnings. Although he was somewhat familiar with Penrose's pattern, he did not yet connect his own work with this pattern until long after its discovery.

At the time of his crucial experiment, Schechtman was alone in the laboratory, but he felt a strong need to share his excitement with someone else - this is a common feeling among people who make a discovery at the moment of discovery itself. Shechtman went out into the corridor of the department, but no one was there, so he returned to his electron microscope and conducted a series of additional experiments to verify his findings. Everything was ready and ready for the announcement of the discovery within a few days. However, two years passed until Shechtman published his discovery.

For a long time, Schechtman was lonely in the belief that he had indeed discovered something new. Immediately after his experiment, he began to check at the Standards Institute in the USA with his colleagues if any of them knew anything about rotational symmetry of the 10th order, but instead of getting factual answers, he became the target of ridicule. The polite ones among his colleagues tried to explain to him that he must have observed a completely different phenomenon, and one of them even gave him a basic book in the field of X-ray crystallography in order to help him understand that what he thought he saw was simply an impossible finding. Shechtman was offered several explanations regarding the resulting pattern, among them the phenomenon of twin crystals, in which two crystals grow that originate from a common side and have unusual symmetries. Another explanation was that there may be a defect in the crystal that gives rise to the pattern that creates this impossible symmetry. The irony in this situation was that when Shechtman himself was a student, in one of his exams he had to prove that 5th order symmetry is not possible at all in crystals.

Dan Shechtman was born in Tel Aviv. His mother's family came to Israel on the second immigration, in 1906, and his father's family came to Israel on the fifth immigration, in 1930. Both families came from Russia. Shechtman attended elementary school in Ramat Gan, and when he was 14 he moved to Petah Tikva. His family's houses were always crowded, which is why he aspired to build a spacious apartment, with a separate room for each of his four children. In his youth, Shechtman was active in the Zionist-Socialist movement, but he was never involved in communist ideology. He appreciates that the movement in which he was active gave him important values ​​and shaped his character thanks to the value of evil. Various activities were held in the movement, including physical exercises and field trips for a whole week in the desert that challenged their endurance in difficult conditions.

At the age of 18, Shechtman enlisted in the army. At the end of his training, he was selected for a special course in psychology and interviewing, and utilized this training for the remaining two and a half years of his military service. In 1962, he began his studies at the Technion in mechanical engineering, a field that had been his dream since childhood and from the moment he read the books of Jules Warren. He was always a good student, but never one of the best. When he completed his graduate studies in 1966, he was given the opportunity to pursue graduate studies. He made a living tutoring students, and at the same time, began his research. He attended all the courses in the fields required to obtain his degree in metallography, including X-ray crystallography and electron microscopy. When the first electron microscope arrived at the Technion, Schechtman was among the first students who became experts in working with him. Upon completion of his master's degree, Shechtman continued to study for a Ph.D. Titanium alloys and their properties - an important topic in the field of aviation - became the subject of his doctoral research. When he received his doctorate, Shechtman wanted to stay at the Technion, but he was told that he would first have to gain experience for several years abroad.

In 1972, Schechtman sent applications for post-doctoral studies to hundreds of universities and research institutes around the world and received a positive response from two of them. The offer he accepted was at the US Air Force Research Laboratories near Dayton, Ohio. He began researching titanium-ceramic alloys there for the next two and a half years. He and his family considered staying in the US since no offers came from Israel, however, in the end, the Technion decided to hire him as a researcher. Shechtman's family returned to Israel in 1975 and he began his work as a lecturer in the metallurgy unit that was within the mechanical engineering department, and which over the years became an independent materials engineering department.

Shechtman was not at all afraid to reveal secrets from his work; The opposite was true - he tried to talk to anyone he could hear about his surprising experiment. He added his "impossible" probability pattern to a Christmas greeting card in order to spread the word about it. His funder at the American Research Institute hung this greeting card on his office wall. Shechtman didn't know what else to do; He did not have additional experiments that would make his discovery more grounded, since in the eyes of his spirit his observation was not ambiguous and was self-evident. He placed his alloy sample in the electron microscope from time to time to look at the pattern again as if to check that it was indeed there. And she was.

Shechtman returned to the Technion and continued to try to find colleagues who would conduct professional discussions with him. In the end, he found one such - Ilan Belch, who was an expert in X-ray diffraction. The two began to develop models of structures that might produce the pattern of probability that Shechtman observed. They built a model that was composed of icosahedral parts; This body, the icosahedron, has 5-order symmetry. Once they had created this model, their thoughts began to converge on a McKee paper from two decades ago that published an icosahedron structure that was not part of normal crystallography.

Belch's support encouraged Shechtman's hopes. There was at least one scientist who shared Shechtman's belief that although the findings of his experiments were unexpected, they were indeed true. Since no one else believed in Shechtman's findings, he did not attempt to formulate his observations in the form of an article. Schechtman was in a dangerous situation. The head of his research group feared that he would have to protect his group's reputation by opposing Shechtman's findings and ultimately decided to remove him from his research group. At the Technion itself, Shechtman had not yet served as a full professor and he did not feel that there was a sufficiently supportive atmosphere to take a step forward, which would be risky.

A more established scientist would perhaps hasten to publish findings like these lest others precede him in doing so. On the other hand, a more established scientist might also be very cautious about publishing a discovery that others consider impossible. Shechtman was convinced that he had an innovative observation, but he was troubled by the fact that he did not have the possibility to provide a reliable explanation for it, and this feeling restrained his intention to publish it. After some time, he and Balch proposed a structural model that might computerically produce the probability pattern that Schechtman observed. When Shechtman finally decided to submit the manuscript in which he and Balch explained their experiment, he did so hesitantly. The information was there, but an unskilled reader could have missed it, since it was buried under mountains of information about the iron-manganese system. Although the article was more like a report in metallurgy, it was submitted for publication in the field of physics, in the scientific journal Journal of Applied Physics. The editor-in-chief of the journal returned a negative answer to Shechtman in which he stated that the manuscript was not suitable for his type of journal - and unbelievably - that the findings would not be of interest to physicists. It is interesting to know what the same editor thought to himself after a few years when there was a flood of articles on this topic, also by physicists, after Shechtman finally managed to publish his experiment.

Shechtman and Balch's manuscript was not drafted in a simple way, so they too, in addition to the editor, were responsible for its failure to be published. However, it is not so rare that it is so difficult to publish a sensational and original discovery. Of course, bad articles are likely to be rejected. However, this is often the fate of a manuscript reporting particularly innovative results. This conservatism exists in the conduct of the most prestigious journals and in the most prominent form. Since Shechtman-Blach's manuscript was indeed worded more as a report regarding research in metallurgy than in physics, they decided to submit it again to a journal in the field of metallurgy where it did appear later, however this publication had no effect on future developments.

Shechtman knew that he needed not only a plausible explanation for the phenomenon he had seen, but that he also needed to significantly improve the presentation of his findings. This is why he turned to a request for assistance from John Kahan, an emeritus scientist who worked in the same department where Schechtman was at the US National Standards Institute. Kahan was familiar with Shechtman's discovery, but for two long years he too did not believe in its innovation. Now he changed his mind, and Shechtman, who was grateful to him for this, invited Kahan to be a co-author of the paper. At this point, Kahan himself added another writer, Denis Gratias, a young French mathematical crystallographer who helped design the mathematical form of the findings. Belch's model is not included in this article, but Schechtman added his name out of professional loyalty. They submitted the new manuscript to the prestigious journal Physical Review Letters, where it was accepted for publication without delay, appearing on the fourteenth of November 1984.

The article bore an innocuous-looking title: "A metallic state with long-range directional order without copy symmetry". The impact of the article was enormous, as if a great dam had opened. Scientists, especially theorists, studied related issues, and those who were familiar with the current literature could easily relate their work to the Penrose pattern, McKee's probability diagram, and Shechtman's discovery.

Within weeks of the publication of Shechtman's article, another article - completely theoretical - appeared in the same journal by Dov Levin and Paul Steinhardt from the University of Pennsylvania. Levin-Steinhardt's journal arrived on the second of November - that is, less than two weeks before Shechtman's article was published, and this fact was not accidental. The circumstances are known from Levin's own words. They got to know Shechtman's manuscript already in October thanks to a professor from Harvard to whom a copy of the article was sent from Kahan. By that time, Levin and Steinhardt had already produced a simulation of a diffraction pattern that resembled Shechtman's experimental pattern. Levin and Steinhardt realized that they had to hurry with the publication of their theory since they realized that Shechtman's experimental discovery would lead to great interest.

Levin and Steinhardt's article bore an elegant title - "Quasicrystals: a new family of ordered structures", thus he first gave the name to the new structures that led to the acceptance of Shechtman's probability pattern. Some argue that giving a name to a discovery may be as important as the extent of the discovery itself. A scientific discovery appears sooner or later in any case, and if not thanks to this scientist, then thanks to another scientist. Contrary to that, giving a name to a discovery is an action that belongs exclusively to that person who created the name, and is unique to him. And yet, it cannot be denied that the discovery itself and not its name influences science and the application of its fruits. This must be remembered, since in the case of the discovery of the quasi-periodic crystals, the discovery, which was first given the name by Levin and Steinhardt, could have been lost in the details. In Levin and Steinhardt's first article, which was clearly written in light of Shechtman's influence, Shechtman's discovery constitutes the tenth place mirror out of all 13 place mirrors.

The discovery of quasi-periodic crystals was an important event in the fields of physics, crystallography, materials science, chemistry and mathematics, and inspired even artists who create sculptures and paintings depicting these new structures. Penrose patterns have become popular decorations. The story of the quasi-periodic crystals demonstrates the complex interrelationships between different fields of science and human activities. There were scientists, such as Alan McKee, who were much more mentally prepared for Shechtman's discovery than Shechtman himself, however, to Shechtman's credit, it can be said that as soon as he discovered his findings, he began to handle them in an experienced manner. He certainly made his mark in the annals of the materials field. Besides his training in materials science, which included specialization in X-ray diffraction and electron microscopy, Shechtman's tenacity and perseverance were probably the most important qualities that led him to complete his discovery despite the ridicule and rejection from "experts".

Although large parts of the scientific community accepted the discovery of quasi-periodic crystals as a new form of materials, a number of particularly distinguished scientists avoided it for many years. As Max Planck said, who developed the quantum theory - one of the most important discoveries in the science of the twentieth century - "A new scientific truth does not conquer hearts by convincing those who oppose it to "see the light", but because those who oppose it, in the end, die, and it grows A new generation that knows her." The same is true for the discovery of the quasi-periodic crystals.

Schechtman experienced great frustration during the second half of the XNUMXs. The main opponent of the universal acceptance of the existence of the quasi-periodic crystals was Linus Pauling, undoubtedly one of the great chemists of the twentieth century. Until his death he maintained his claim that what Shechtman observed was nothing but twin crystals and that quasi-periodic crystals simply do not exist. Pauling himself was a graduate of the method of X-ray crystallography, but he did not really believe in electron crystallography, while Shechtman conducted his experiments in electron crystallography. It is Pauling's position that persuaded Shechtman more than any other position, since Pauling was a great authority in his field, and even many of those who would have accepted Shechtman's argument, avoided it out of a desire not to hurt Pauling by choosing the side of his opponents.

Pauling remained abreast of new developments in science even as his primary interest diverted to other subjects. When he heard about Shechtman's discovery, he asked Shechtman for additional details, which he provided. When Pauling suggested that Shechtman conduct additional experiments, Shechtman agreed and formulated his results in a personal paper just for Pauling. Pauling had no problem with Shechtman's experiment, but only with his interpretation of his observations. Eventually, Schechtman visited Pauling and presented his findings to him in person. Pauling had many questions, but he was not convinced.
They saw each other again and again at conferences, always cordial to each other, but never reached an agreement. Schechtman's last personal meeting with Pauling was held at an important lecture given by Pauling, in which he mentioned quasi-periodic crystals in the most negative way. Shechtman himself was present in the audience there, and was not known to any of those around him. In Schechtman's mind, on this occasion Pauling resembled more a politician and preacher elated by the adoration of the masses than a scientist.

Pauling did his best to cast doubt on the discovery of quasi-periodic crystals and punched Shechtman's name without knowing he was in the audience. When Schechtman couldn't take it anymore, he turned to his neighbors in the audience and declared that Pauling was wrong. Their reaction to his statement was really close to physical blows with him.

An important turning point for accepting the existence of non-periodic structures came in 1987 when quasi-periodic crystals large enough to be used in X-ray diffraction experiments were prepared. Schechtman presented these new findings at a conference of the International Crystallographic Association in Perth, Australia. The audience was convinced by the results and immediately afterwards, a committee was established to redefine the term "crystal" in order to include Shechtman's new materials, which from this point on were called quasi-periodic crystals.
People sometimes call Shechtman a "type" and claim that he has the ability to polarize the people around him. He may be flexible on many issues which he considers unimportant; In other cases he is extremely opinionated and does not seem to succumb to social pressure. He cherishes his independence, tends not to take things from other people and as a principle is not ready to owe anything to someone who is not among his close friends.

From the moment the discovery of the quasi-periodic crystals appeared in 1984, Shechtman's life changed. He became a celebrity, abroad almost immediately, and then gradually in Israel as well. Initially, it was the non-scientific media that exposed him, and thus the "Haaretz" newspaper published an article on its front page about Shechtman and his discovery. In the next step, he began to receive invitations to lectures in Israel, was elected as a member of the National Academy of Sciences, and won the most prestigious awards in the country in addition to international recognition. There were times when he gave about thirty invited lectures every year, all over the world. He became a full professor in 1987.

The applications of the quasi-periodic crystals began to emerge much more slowly than the scientists anticipated. There is still hope for the development of applications in the fields of manufacturing kitchenware coated with quasi-periodic crystals. Some scientists believe that its advantages are greater than those of the Teflon material, especially due to its much greater rigidity and its ability not to be scratched or peeled off, unlike Teflon. Shechtman was never involved in patent applications related to his discovery.

Soon the field of quasi-periodic crystals began to develop more than Schechtman could have ever imagined for him. He must be shocked to see the development of the field: the meetings, books and research groups dealing with it all over the world. Shortly after the publication of the discovery, Shechtman's main research topics were diverted to other fields, since he was unable to obtain funding for his quasi-periodic crystal research. Apparently he was less stubborn in raising funds than in sticking to the idea of ​​his discovery. It is also possible that the reason was that he was interested in new adventures and discoveries. Despite this, after a period of time Shechtman returned to the field of quasi-periodic crystals where he is now considered the greatest of all - not because of his age but because of his professional authority.

How and why did the winner of the 2011 Nobel Prize in Chemistry, Dan Shechtman, persist even though he was rejected?

Prof. Hargitai in an interview with the Hidan website in March 2011: Prof. Dan Shechtman's discovery of quasi-crystals has implications for chemistry, physics, materials engineering and even for art

to the book page on the publisher's website