Tailoring chemical bonds
Specific identification of solids that drastically change their properties during crystallisation.
Solids can have two structurally very different states: crystal and glass. While the short-range order of the atoms in both states is generally very similar, only the atoms of the crystal have a long-range order. The similarity of the short-range order is attributed to the similarity of the chemical bonding between the atoms in both phases. In their joint publication Tailoring Chemical Bonds to Design Unconventional Glasses, Professor Matthias Wuttig from the I. Institute of Physics at RWTH and JARA Institute Green IT at Forschungszentrum Jülich, and Carl-Friedrich Schön from I. Institute of Physics at RWTH, together with researchers from Milan, Liège, and Marseilles, describe their approach to the design of chemical bonds and thereby the properties of functional materials.
Schön and Wuttig distinguish between two types of solids – those in which crystal and glass show the same chemical bonding and those in which the chemical bonding differs significantly in both states. This is why the latter materials also have a significantly different short-range order of atoms and therefore different properties than in the crystalline state. Only materials whose crystals form so-called metavalent bonding exhibit this behavior. With the help of quantum mechanical calculations, the physicists can draw a map that can identify these special materials, making it possible to specifically identify solids that drastically change their properties during crystallization. The Aachen-based physicists have published their findings in the renowned journal Proceedings of the National Academy of Sciences (PNAS).
Original publication
