In my research group, we are working on the synthesis of tellurate materials. These are salts of the telluric acid H₆TeO₆ or the telluric acid H₂TeO₃. The tellurium atom in these compounds has either the +VI or +IV oxidation state. In addition, the tellurium atom has a high degree of flexibility in its coordination environment, which makes these compounds structurally extremely interesting. As the diagram shows, tellurium can be surrounded by oxygen atoms in many different ways. We are interested in structural changes and the associated changes in physical properties that can be achieved by varying the additional synthesis parameter pressure.

The focus is on a special synthesis method, the multianvil high-pressure high-temperature synthesis, the elucidation of the crystal structure using X-ray methods and, in particular, the properties of these new materials. Transition metal tellurates often exhibit multiferroic phenomena, i.e. several simultaneously occurring states of organisation such as ferromagnetism in addition to ferroelectricity or piezoelectricity, which can be influenced by changes in the magnetic or electric field. Other materials are highly interesting with regard to their non-linear optical properties. In the field of alkali metal tellurates, lithium or sodium ion conductivities are of particular interest to us.