Claudia Draxl is Einstein Professor for solid-state theory of the physics department of the Humboldt-Universität Berlin. There the SOLgroup, led by Claudia Draxl, focuses on condensed-matter theory and computational materials sciences, working on theoretical concepts, development of computer codes, as well as their application to a variety of materials.
»Creating new materials on computer«
Material design on the computer screen? Tell us more.
We apply computational methods to the physical properties of materials, which can include anything from simple metals to semi-conductors, or even plastics. We also analyse and try to improve on the methods we use to compute material properties. To do this, we develop and write computer programs, and apply them to a wide range of materials. Whether our goal is to mix different material components, or even just replace individual atoms, we always want to innov- ate. For us, that means producing a new material with properties that did not previously exist. Computers facilitate this process. They help us predict how different properties will change without the need to actually produce the materials.
Which materials have captured your interest?
Right now, I would definitely say the hybrid materials. This is a group of nanostructured materials with interfaces which bring together components with different properties. One example is the combination of carbon nanotubes and organic molecules – two very different materials. Carbon nanotubes are robust; they also have very good electrical properties. But they are useless for constructing optoelectronic elements, because they cannot emit or capture light in the visible range. However, there are many molecules among their organic counterparts that can do exactly that. When we introduce them into the nanotubes, we can create a new material that combines the mechanical and electrical properties of nanotubes with the light-absorbing properties of the organic molecule. The basic idea in this case is to produce a light-emitting nanoobject in the hopes of someday using it for optoelectronic materials. That includes elements we need for flat screens, for example.
Does creating a new material basically mean you have outsmarted nature?
We leave the actual work of “outsmarting” nature to the experimenters. They are the ones who produce what we decided was a good material on paper, or in our case on the screen. But it’s a long process. The path to finding a new material until it can be applied usually takes about 20, and sometimes even 30, years. My work is in the area of basic research. But that does not prevent me from thinking about what could be useful in the future. One case is thermoelectric materials, for ex- ample, which is a class of materials that could be very efficient in transforming exhaust heat into electrical energy. I believe that we need to stick with the basic questions so that we can keep moving forward.
Photo: Emmanuele Contini