Rohrer (Rohrer), Heinrich( Swiss physicist, Nobel Prize in Physics, 1986)
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Biography Rohrer (Rohrer), Heinrich
genus. June 6, 1933
Swiss physicist Heinrich Rohrer was born in g. Buchs, in eastern Switzerland, the son of a traveling salesman for disseminating industrial goods, Hans Heinrich Rohrer and Catherine (nee Ganpenbeyn) Rohrer. As a teenager, R. excellent time to physics and chemistry, and showed great ability to ancient languages of Latin and Greek, but modern languages were given to him with difficulty. After high school he decided to devote himself to the study of ancient languages, but then changed his mind and enrolled at the Zurich Federal Institute of Technology to take up physics and mathematics. His doctoral thesis was devoted to the influence of pressure and volume effects on the superconductivity. In 1960, Mr.. for this work he was awarded a doctoral degree.
After a year of service in the Swiss Army R. was enrolled for a post-doctoral research in Ratdzhersky University in New Brunswick (New Jersey), where he spent two years researching the phenomena of superconductivity. In 1963, Mr.. He returned to Zurich and started working in the research laboratory of the company 'International Business meshins'. (IBM). The exception of 1974/75, the school, which is P. spent as a visiting scholar, University of California, Mr.. Santa Barbara, all the rest of the time it remains in the laboratory of IBM.
While at IBM research interests Rohrer moved from other areas of superconductivity in solid state physics. Especially got him hooked on the problems associated with the properties of surface materials, where there are chemical and other kinds of interaction between substances. There were methods to investigate the arrangement of atoms in the material, but there were relatively few approaches to understanding the very different behavior of atoms on the surface. In attempts to explore the surface was difficult for a long time hindered progress. These difficulties were so great that Wolfgang Pauli once said 'surface, of course, was the invention of the devil! "
In 1978. to R., seek to understand the processes occurring on the surface, joined just finished graduate of Frankfurt University Gerd Binnig. Soon the two scientists were able to propose a new approach to the study of surfaces on the basis of quantum-mechanical effect known as tunneling. The effect of tunneling is a direct consequence of the Heisenberg uncertainty principle (named in honor of German physicist Werner Heisenberg), which states that the position and velocity of a subatomic particle can not simultaneously be known. Consequently, such a particle, such as an electron does not behave like a particle, but as a vague 'cloud' of matter. This oblakoobrazny nature of subatomic particles allows them to 'tunnel', or to penetrate, through the two surfaces, even if they do not touch the tunneling phenomenon was experimentally confirmed Ivar Ivar Giaever in 1960
. By the time P
. and Binnig began their work, the effect of tunneling was well known. Some physicists have even used this effect for a set of data on the boundaries separating the individual layers in the 'sandwich' of materials R. Binnig and chose a different principle, forcing the electrons to tunnel through the vacuum. The highest achievement in the development of the proposed approach was the invention of a new device, called a scanning tunneling microscope. The main idea of this device is to scan the surface of the solid in vacuum with the tip of a sharp needle. If between the sample and the tip of the needle voltage is applied and the distance is small enough, the electrons tunnel from the tip of the needle sample. The flow of electrons is measured as the current tunneling. Power of the tunneling current depends on the distance between the sample and the needle tip and is expressed by an exponential function of distance. Leading needle on the model and the current dosing, the researchers are able 'to map' the location of the microscopic (atomic size) the hills and valleys on the surface of the sample.
Despite the enormous technical difficulties, P. Binnig and were optimistic. As noted later, R., 'we were quite confident of success. From the beginning we knew that it would be important to moving forward is surprising is that we have been able so quickly to achieve the desired '. The first successful test of a scanning microscope P. Binnig and spent the spring of 1981. With the participation of two other members of IBM Christopher Gerber and Edmund Veybelya they managed to reach a solution 'rough' on the surface of calcium-iridium-tin crystals (CaIrSn4) height of only 1 atom. Ironically, when they first sent an article reported on the results obtained in the magazine, the reviewer has rejected it, finding 'interesting enough'.
. The biggest obstacle to a group of IBM was the need to eliminate all sources of vibrational noise
. The strong dependence of tunneling current on the distance between the sample surface and the scanning tip, the position of the tip must be controlled to within a percentage of diameter of an atom. If you do not take sufficient precautionary measures, the street noises and even the steps of passers-by can completely disrupt a delicate operation as the work of scanning microscope. Initially P. Binnig and intended to solve the problem of noise, putting the microscope on a heavy stone plinth, which are isolated from external disturbances in the building of the laboratory with special shock absorbers of the flattened tires. Sam microscope was suspended over a bowl of a superconducting lead with permanent magnets. To move the needle with the greatest accuracy experimenters used piezoelectric materials, which are reduced or expanded under the influence of the applied voltage.
. In the future, the microscope has been greatly improved in comparison with such a primitive first version
. The scanning tunneling microscope (with the exception of the vacuum chamber) fits in the palm and can resolve the vertical size of the details in 0.1 angstrom (1010 m) or, in other words, one-tenth the diameter of a hydrogen atom. Resolution of the scanning tip width of only a few atoms can resolve details of the horizontal plane no more than 2 angstroms. Currently managed to make the tip width of only 1 atom. In 1986. in laboratories around the world were at least 40 scanning tunneling microscopes, and the two companies started to release commercial versions of these devices. The scanning tunneling microscope, in addition to the vacuum works in other media, including air, water and cryogenic liquids. It is used to study not only inorganic but also organic substances, including viruses and deoxyribonucleic acid (DNA).
In 1986. R. Binnig and were awarded (one half) of the Nobel Prize in Physics "for the creation of a scanning tunneling microscope '. The other half of the prize was awarded to Ernst Ruski for his contribution to the creation of an electron microscope. At the presentation ceremony of the winners of the representative of the Royal Swedish Academy of Sciences said:
'The scanning tunneling microscope is something completely new, and we still have seen only the first of its applications. But now it is clear that the researchers structure of matter, an entirely unknown region. The great achievement of the winners is that, taking as a starting point of their earlier works and ideas, they were able to overcome the enormous experimental difficulties encountered in the construction of the device the required accuracy and stability. "
In 1961. R. married Rosemary Eggar. In the couple's two daughters. When asked to indicate their characteristic feature of RA, a reputation gentle and modest man, replied: 'Those who know me understand my. For those who do not know me, say something useless. "
In addition to the Nobel Prize, P. Binnig and have been awarded, and other awards for his work. In 1984. they received a prize Hewlett - Piccardi European Physical Society and the International Prize for physics, King Faisal, awarded by the Government of Saudi Arabia.