Harald Rose (Bremen, Germany; 1935) obtained his PhD in physics from the Technical University of Darmstadt, where he would return as a professor on two occasions: from 1971 to 1975 and 1980 to 2000. A theoretical physicist, he has spent part of his research and teaching career in the United States, where he worked in a series of centers including the Institute of Applied Physics at Cornell University and the national laboratories of Oak Ridge (Tennessee), Argonne (Illinois) and Lawrence Berkeley (California). Appointed senior professor at the University of Ulm in 2009, his scientific production spans around 200 papers and 110 patents.
Speech
Basic Sciences, 6th edition
No living being can see atoms with the naked eye, and it is doubtless this lack that enables us to negotiate our human-scale reality. Otherwise how could we simultaneously look at a step and not fall over it? For technological man, however, the limits imposed by the biological eye can be a disadvantage. We now know that the properties of the materials that surround us in our daily lives —semi-conducting, insulating, biocompatible, magnetic, rigid, optical, etc.— depend on events at the atomic scale. Technology, we might say, is born in the spaces our senses cannot reach, which explains why zooming in on materials till we can see their atoms is a long-held ambition. Or was, rather, because now we can.
Harald Rose, Max Haider and Knut Urban, creators of the device that allows electron microscopes to see the atomic fabric of materials, are the latest winners of the BBVA Foundation Frontiers of Knowledge Award in Basic Sciences. Aberration-corrected transmission electron microscopy, the name of Haider, Rose and Urban’s technique, shows the position of each atom and its interactions with the rest.
In the words of the jury’s citation, it is now a vital instrument in “many areas of fundamental and applied science,” allowing to study “the consequences of subtle atomic shifts in the properties of materials.” Controlling these shifts holds out the promise of creating better catalysts, more efficient solar cells, membranes for capturing CO2 … The list is likely to run as far as the imagination of scientists and engineers can stretch.
The unit of distance that comes into play at the atomic scale is the picometer: one trillionth of a meter. The average atom measures one hundred picometers; far smaller than the wavelength or width of light detectable to the human eye, which is accordingly unable to see it.
The aberration-corrected transmission electron microscope can pick up changes in the positions of atoms of just a few picometers. And if anyone doubts the importance of this advance, consider that it is with atomic displacements of this size that data are stored on a pen drive; the digital bits in today’s memory sticks are oxygen atoms that have barely shifted from their original position. The story of how Rose, Haider and Urban managed to “open the door to the atomic world,” as Urban puts it, has all the ingredients of the best adventures: a long-standing challenge that had scientists about to concede defeat, a revolutionary paper rejected by a leading journal, perseverance, and, of course, teamwork.
The starting point was the problem itself. For electron microscopes to be able to resolve to the atomic scale, an image-blurring phenomenon known as spherical aberration would have to be corrected.
In electron microscopes, the specimen is illuminated by an electron beam much finer than visible light and therefore able to detect atoms. The way to nullify spherical aberration would be to create a corrective lens with magnetic fields that focus the electrons, even when they are scattered in large angles. But this had been attempted without success since just after the electron microscope was invented, in 1937.
Harald Rose, a theoretical physicist, started grappling with the problem in the late 1960s when still a PhD student in the Institute of Theoretical Physics at TU Darmstadt (Germany). He almost got there, but the project was abandoned after his thesis supervisor, Otto Scherzer, died in 1982. The obstacles seemed so insurmountable that in the late 1980s the U.S. research agency decided to stop funding investigations in the area, creating a domino effect that cut short research the world over… except in Rose’s head.
It was around this time that the theoretician, who admits to a stubborn streak, encountered the solution when working on something else. His idea was to use hexapoles, a kind of magnet that was known to solve spherical aberration but had not been tried because it caused other distortions. By positioning two hexapoles symmetrically, he conjectured, it should be possible to prevent any added distortion. “I was sure it would work,” declares Rose, for whom this has been his life’s work: “I had the solution in five minutes, but it took me twenty years to get to those five minutes.”
Haider (Freistadt, Austria; 1950) originally trained as an optician. He was 26 when he decided that he was more interested in the underlying science and started to study physics. His specialty was microscopy with visible light —optic microscopy— until he met Rose at Darmstadt. He was quickly convinced that “Rose’s idea to get round the main impediment in the way of atomic resolution would eventually work, and it was simply a question of persistence and finding the money.” Funding was certainly a problem. After the disbanding of Rose’s Darmstadt group, Haider moved to the prestigious European Molecular Biology Laboratory (EMBL) in Heidelberg. Despite being appointed in 1989 to lead the Electronic Microscopy Group, he could not raise the funds for the aberration correction project.
It was then that Knut Urban (Stuttgart, Germany; 1941) entered the scene. An expert in new materials, he was seated, quite by chance, near to Haider and Rose at the 1989 conference of the German Society for Electron Microscopy. “They were looking for a partner with an excellent reputation in my area, and for me it opened the door to the atomic world,” recalls Urban, convinced that in science “if you don’t take risks, you don’t make discoveries.” He cites two factors to explain how they finally got their funding, in 1991: the group’s three-way interplay between a theorist, an experimentalist in electron optics and an expert in new materials; and their decision to approach the Volkswagen Foundation, which, he explains, funds research “that is not necessarily all that close to practical developments.”
The first images captured with an aberration-corrected transmission electron microscope were obtained in 1997, and although Nature initially declined to publish them — “As is so often the case in science, the really new aspects of the work were not immediately recognized,” remarks Urban — it did so in 1998, to considerable acclaim. By 2003, the first commercial aberration-corrected microscopes were already in the labs.
The laureates have also taken a hand in the product’s commercialization, more from necessity than choice. While the project was still in development, EMBL’s management changed and Haider’s group too was shut down: “We were forced to leave and to continue the exciting work at our own company.”
