Electrons and ions are the building blocks of a material. The properties of a material are determined by the interaction among the electrons, between the electrons and the ions, as well as between the ions. Electrons, being much lighter than ions, must be treated as quantum particles and play a decisive role: they are the glue that binds ions together, they conduct electricity and heat, they are responsible for magnetism and they play a central role in the interaction between light and matter. Nowadays, the electronic structure of many materials can be calculated reliably from "first principles", that is, from the fundamental equations of quantum mechanics and electrodynamics without adjustable parameters. In addition to the physical insight provided by these calculations, this ability makes it possible to guide experimentalists searching for new materials with desirable properties without having to synthesize them in the lab first, the so-called computational materials design.

In the last few decades, many new materials hosting intriguing and fascinating properties have been discovered and synthesized. One of the most famous examples is the high-temperature superconductors. For these materials, the usual electronic structure methods, which treat electrons as independent particles moving in a common potential, break down. Here, the interaction among the electrons cannot be approximated by a common potential but must be taken into account explicitly, resulting in strong correlations among the electrons and collective behavior. To treat these electron correlations accurately is one of the most important goals in condensed matter physics.  The importance of electron correlations cannot be overemphasized: correlations are also able to generate novel phases, including interaction-driven insulators and unconventional superconductors. In the division, we are studying these strongly correlated materials by developing, extending and applying new methods that are able to reliably handle strong correlations.

Faculty at the division working in the area [links open the person's homepage]:

• Ferdi Aryasetiawan
• Erik van Loon