Journey into the realm of the nanometre

Text: Sven Titz

As one of the most productive and important minds in his field, the physicist Piet Brouwer focuses on researching quantum transport and solid state theory. In this way, for example, he can contribute to the development of super-quick computer memories. At the Freie Universität Berlin he is to head the newly founded Dahlem Center for Complex Quantum Systems.

The things that Piet Brouwer focuses on are incredibly small. They measure barely more than a nanometre, i. e., one millionth of a millimetre. A comparison helps us to put this into perspective: The relationship between a nanometre and a metre is like that between a hazelnut and the Earth. In the realm of the nanometre, the laws of classical physics no longer apply. Instead, strange quantum effects appear. Thus, for example, several processes cannot be predicted and instead proceed randomly, such as radioactive decay. Some particles also appear to be present in several places simultaneously – until we take a closer look. In short, here we are no longer dealing with the usual solid matter, but with billowing particle clouds. Physicists refer to systems on the borderline to these quantum effects, systems, whose dimensions are in the nanometre field, as mesoscopic.

Super-swift computer memory

The 37-year-old Dutchman is regarded as one of the world’s leading experts in the mesoscopic sphere. As a Humboldt Professor, he will in future head the Dahlem Center for Complex Quantum Systems which is currently being established at the Freie Universität Berlin. The idea is for theoretical physicists from several different disciplines to work together at the new Center to explore questions about the nanosphere and neighbouring research fields. The theorists face high expectations, as anyone who understands the physics of mesoscopic systems already has basic knowledge of the latest techniques in nanoelectronics.

Brouwer cites the development of super-quick magnetic computer memories as one example of his research. At present experts are searching for a compromise between a hard disk and Random Access Memory. We want to be able to save information permanently, as on a magnetic hard disk, but also access that information in a flash, as with the rapid RAM. When it comes to the nanomagnetic materials that are possible options for the desired memory Brouwer certainly knows his stuff.

The dream of industrial nanomodules

Brouwer’s work could also become important for the manufacture of computer processors in future, namely, if the process of miniaturisation continues as it has done thus far and in a few years producers cross the border to the mesoscopic sphere. In that case computer processors will need to be constructed in a completely different way from today, says Brouwer. He has already started exploring the theoretical foundations.

Another of Brouwer’s fields of research is the properties of “graphene”. This is a layer of graphite consisting of carbon atoms in a honeycomb lattice only one carbon atom thick. Experts are currently debating whether or not we can use this substance for nanoelectronic components. “If we were able to produce graphene industrially, it would be a dream”, says the scientist. He aims to contribute to its realisation by researching the physical fundamentals.

Brouwer did not have his heart set on physics right from the start. When he started studying in the Dutch city of Leiden, he was still unsure whether he wanted to be a mathematician or a physicist, which is why he studied both subjects. As a student working in laboratories for experimental physics, he acquired a taste for it. Although he remained a theorist in terms of methodology, from then on he focused solely on practical aspects.

So what, having worked in the USA since 1999, is calling him to Berlin? The excellent conditions at the Freie Universität and brilliant colleagues are two of the reasons for his decision. “Here I can conduct my research at least as well as in the USA”, says Brouwer, adding that in Germany one is less reliant on raising project funds at short notice and there is more room for researching the basics than elsewhere. He also praises the excellent education of physicists at German universities and wishes to make a significant contribution to this in future.