Brazil was the venue of pioneering research studies involving the physics of graphene, a densely packed, one atom-thick carbon film. Graphene had been the subject of a study conducted by the two scientists who were laureates in this year’s Nobel Prize for Physics: Russia’s Andrei Geim, 51 years old, and Konstantin Novoselov, 36 years old, from the University of Manchester in England. Since 1999, a group led by physicist Yakov Kopelevich, from the Materials and Devices Laboratory at the University of Campinas (Unicamp) Gleb Wataghin Physics Institute, has been studying the physics of graphene. Kopelevich’s group achieved converging results with the findings of Geim and Novoselov, who had isolated flakes of graphene from the graphite used in ordinary pencils and had demonstrated the properties of graphene.
As a result of the research studies, for which FAPESP and the National Council of Scientific and Technological Development (CNPq) provided funding in the amount of R$ 1 million, Kopelevich and two students (José Henrique Spahn Torres and Robson Ricardo da Silva) identified, at the beginning of this decade, the electric and magnetic properties of graphite that had never been known to exist. Their work now helps scientists understand why graphite sometimes acts as an electricity-conducting material and at other times, as an insulating material. Kopelevich and his team pioneered the measuring of the Quantum Hall Effect and the detection of Dirac fermions in this material. The related articles were published in Physical Review Letters in 2003 and 2004.
The Quantum Hall Effect coordinates the movement of electrically charged particles – electrons, in the case of graphite – on flat surfaces. This effect was discovered by Klaus von Klitzing, a physicist from the Max Planck Institute, whose research earned him the 1985 Nobel Prize in Physics. The effect is the version for the microscopic quantum world of a phenomenon identified one century earlier by American physicist Edwin Hall. Hall observed the effect named after him when he applied a magnetic field to conducting material through which an electric current was flowing. The magnetic field, applied perpendicularly to the conducting material, caused a deviation in the electrons’ path. The electrons accumulate at one extremity of the conducting material and cause a transverse electric field to be created. When physicists submit any kind of material to low temperatures and to a magnetic field, the increased intensity of this field makes the Hall resistance grow in proportional leaps, remaining constant between one peak and the other. This phenomenon takes on the shape of graphs that resemble a staircase interspersed landings. Kopelevich and his team had detected this peak pattern in the Hall resistance and identified it as a consequence of the variation of the magnetic field in the graphite. Kopelevich and his fellow researchers described their findings in an article published in Physical Review Letters in 2003.
In another article published in the said journal, Kopelevich and Igor Lukyanchuk (the latter from the University of Picardie Jules Verne, in France) described another property of graphite. When they varied the intensity of the magnetic field, they noticed that the free electrons showed unusual behavior, described by the quantum physics equations created in 1928 by British physicist Paul Dirac: these electrons move like mass-free particles, like photons, which are the basic units of light.
In 2005, Andrei Geim, in England, and Philip Kim, in the United States, noticed the same effect in graphene sheets. “We observed the great contribution of Dirac fermions and concluded that the graphite had uncoupled graphenes. Similar experiments were later conducted on graphenes by Geim, Novoselov and others, who developed excellent studies”, said Kopelevich to Pesquisa Brasil, a radio program aired by Pesquisa FAPESP. “Brazil is certainly a pioneer in this field, though nowadays the number of research studies on the physics of graphite is not as high as in other countries. But we are working on this”, he added.
Graphene was first described in 1961 by the German chemist Hanns-Peter Boehm. The speed and ease with which the electrons move in this material make it a natural candidate to succeed silicon in high-speed computer chips, even though a lot of research must still be conducted in this respect. As a conductor of electricity, graphene is as efficient as copper. As a heat conductor, it is far superior to any other known material. It is almost transparent, but is so dense that not even helium, the smallest of the gaseous atoms, is able to go through it. Thanks to its light absorption property, the sheet thickness of an atom is visible to the naked eye. Graphene’s carbon atoms are arranged in a hexagonal network that forms an almost flawless honeycomb structure. “It is a big crystal and is a hundred times stronger than steel. We can stretch it up to 20 percent and it has other interesting properties that can be used in different applications”, says Bjorn Jonsson, a member of the Swedish Academy.
Carbon was also a protagonist in the Nobel Prize in Chemistry. Two Japanese scientists and one American scientist were awarded the prize for their work on the so-called palladium-catalyzed coupling reactions, a fundamental tool for the organic synthesis of complex molecules that are widely used nowadays in a variety of fields such as medicine, agriculture and electro-electronics. Akira Suzuki, aged 80, from the University of Hokkaido, Ei-ichi Negishi, aged 75, from Purdue University, and Richard F. Heck, aged 79, from the University of Delaware, began their research into this field more than 40 years ago. They will share the US$ 1.5 million award granted by Sweden’s Royal Academy of Sciences. According to the Nobel Prize committee, the impact of adopting this kind of coupling reaction in the production of molecules for medicine is enormous: one fourth of all current synthesized drugs are manufactured with some variant of the technique. In the field of electro-electronics, the so-called Oleds, or organic LEDs, which are light-emitting diodes, are also created with the help of this reaction.
To manufacture compounds that are more sophisticated or to reproduce – in laboratories – the big molecules found in nature, chemists need to change a characteristic of carbon, the basic element of life: carbon atoms are stable and do not bond easily with each other. Various techniques have been devised to solve this problem. However, none of the existing techniques have proven to be as efficient and clean (no chemical waste is produced) as the palladium-catalyzed coupling reactions. As the name itself explains, in this kind of reaction palladium is the element that stimulates the binding of the carbon atoms. This element makes the carbon atoms – that normally would not bind with each other – reactive. As a result, they form complex organic molecules. Heck was the first scientist to use palladium as a catalyst of carbon ligants. He did this in 1968. In the late 1970s, Negishi introduced zinc compounds to facilitate the action of palladium and Suzuki added boron to this reaction, which led to even better results.
Test tube baby
A technological breakthrough that allowed millions of couples to have children earned the Nobel Prize in Physiology or Medicine. Great Britain’s Robert G. Edwards, professor emeritus at England’s Cambridge University, was awarded the prize for his work on human in vitro fertilization, a technique popularly referred to as a test-tube baby. “His contributions are an outstanding achievement in the field of modern medicine”, said the members of the Nobel Prize committee. The 85-year old Edwards, who is very ill, was awarded the US$ 1.5 million Nobel Prize, but was unable to make any comments on the award. Edwards began his research work on in vitro fertilization in the 1950s. Twenty years later, he created a technique that enabled unfertile couples to have children. This is a process whereby egg cells are fertilized outside the woman’s body and then transferred into her uterus. The first test tube baby – Louise Brown – was born in England on July 25, 1978. So far, more than 4 million babies have been born with the aid of this technique. British gynecologist Patrick Steptoe, who passed away in 1988, was Edwards’ partner in this scientific endeavor. He played an important role in taking in vitro fertilization from the level of technical experimentation to that of pratical medicine. However, as the Nobel Prize is not awarded to deceased scientists, Edwards was the sole laureate. In 1980, Edwards and Steptoe founded the Bourn Hall Clinic in Cambridge. The clinic is a center specializing in in vitro fertilization.
At a time during which capitalism is trying to come out of a major crisis, the Nobel Prize in Economic Sciences was granted to three researchers who proposed and developed a theory able to explain why so many people are unemployed even though companies consistently open up job positions. Peter A. Diamond, aged 70, professor of economics at the Massachusetts Institute of Technology (MIT), and Dale T. Mortensen, aged 71, from Northwestern University, were awarded the prize for their work on creating mathematical models that explain market situations in which there are uncertainties or imperfections in the supply and demand of goods or services. The two Americans will share the US$ 1.5 million prize with 62-year old Christopher A. Pissarides, a native of Cyprus, who teaches at the London School of Economics and Political Science.
The economists’ early research work in this field was conducted in the 1970s and resulted in the so-called Diamond-Mortensen-Pissarides (DMP) model, a tool used to analyze unemployment, the mechanism of salary formation and the impact of public policies on this sector. Although the labor market is the field in which this model is most often used, the model can also be employed to understand the real estate market and other aspects of economics. According to the Swedish Academy, the merit of the economists’ work was that it shows that the classic view of the perfect market does not always find support in the real world. The traditional theory states that buyers and sellers of goods and services meet quickly in the market, without any cost to either party, and that everybody is well informed on the prices of the goods and services. There is no surplus supply or demand for a product and all resources are used fully. In this ideal world, the price of goods and services is equal to the supply and demand. “But this does not happen in the real world”, wrote the Nobel Prize committee. “High costs are often associated with the difficulty that buyers have to find sellers. Even after buyers and sellers meet, the given goods might not correspond to the buyers’ requirements. The buyer might think that the seller’s price is too high, or the seller might think that the buyer’s offer is too low. So the business transaction does not take place and the two parties continue looking for the merchandise elsewhere.” This mechanism is typical of many sectors of the economy, including the labor market.
Peruvian writer Mario Vargas Llosa was awarded the Nobel Prize in Literature for his “cartography of power structures” and “vigorous images of individual resistance, rebellion or defeat”, as emphasized by the Swedish Academy. The 74-year old writer has written more than 30 novels, plays and essays. He is the first South American writer to be awarded the Nobel Prize ever since Colombia’s Gabriel García Márquez won it in 1982. Chinese political activist Liu Xiaobo was awarded the Nobel Peace Prize in recognition of his non-violent activism for democracy and human rights. The nomination placed China’s human rights situation in the limelight, at a time when this country is beginning to avail itself of its impressive economic growth to take on a more prominent role in the international political scene. The Nobel Committee praised Xiaobo for “his long and non-violent battle for basic human rights in China” and restated its belief in “the close connection between human rights and peace”.Republish