Controlling the composition of solids and understanding the relation of composition and structure is the foundation to investigate complex physical phenomena like superconductivity. My group explores the electrochemical navigation within phase systems, where an externally applied potential is used to change the composition of solids postsynthetically. Coupling this precise control of the composition with in-situ X-ray diffraction to characterise the structure, allows to establish a direct link between structure and composition. It also allows to access new (metastable) phases. Subsequently measured physical properties can then be interpreted unambiguously, which provides a rigorous relationship between chemical composition, structure and physical properties.
Not only do we do the postsynthetical electrochemical modifications; we also synthesise our compounds ourselves with various solid state techniques, e.g. powders in sealed ampoules, chemical vapour transport or solvothermally. By employing our comprehensive toolbox of analytical techniques we are able to optimise e.g. the phase purity and the crystal sizes.
Currently, we are focusing on binary iron, cobalt, nickel and copper chalcogenide systems that crystalise in the anti-PbO structure type. This layered structure type not only provides a vast playground to explore varying superconducting properties amongst similar structures but could also yield valuable contributions to battery research on a fundamental level.