Group Leader Profiles

The theory group has a long standing experience in the study of quantum phenomena in the field of atomic, molecular and optical physics. A special focus is on the man-body properties of strongly interacting quantum systems, as naturally realized with dipolar gases, cold atoms in optical lattices, polar molecules, and photons in a Rydberg media. The main research goals are the creation of exotic states of matter with ultra-cold gases, the design of quantum simulators for topological ordered phases and the study of their application for quantum information, as well as the understanding of strongly correlated states.

The group works on the development of novel battery systems, among them fluoride ion batteries and solid state batteries. For the former, the intercalation and deintercalation of fluoride ions leads to a change of electronic properties, and can induce novel magnetic phenomena or superconductivity. The development of catalysts for the oxygen redduction reaction is further connected to the chemistry of oxyfluoride compounds. In addition, we target the development of materials for solid state batteries, considering their sustainability and suitability for circular economy. Methods used in the group comprise solid state and wet-chemical synthesis routes, thin film deposition as well as topochemical low-temperature routes, combined with structural, electrochemical and magnetic characterization and compositional analysis.

• All aspects of modern powder diffraction • Structure determination • Thermochromic / Photochromic / Electronic / Magnetic materials • Microstructure • In-situ/time-resolved • Non-ambient conditions • Rietveld refinement • Parametric refinement • Landau theory / Strain-order parameter coupling • Method of Maximum Entropy

Our research group is at the forefront of creating functional materials through the chemistry of metal–organic frameworks (MOFs) and covalent organic frameworks (COFs) for catalytic applications. We specialize in the fusion of MOF and COF chemistry to develop materials with superior properties, while targeting thermo-, photo- and electrocatalysis, which can contribute to addressing global energy and resource challenges.

Our expertise spans coordination chemistry, organic chemistry, and materials science, supported by an extensive range of analytical techniques. These skills empower us to thoroughly understand and design the synthetic processes, structures, and catalytic behaviors of porous crystalline materials. By leveraging our knowledge and methodologies, we strive to push the boundaries of materials science and chemistry.

We are extending the coupled cluster theory, one of the most successful theories for ab-initio simulations of molecules, to study strongly correlated, extended and periodic molecular systems. We are developing novel coupled cluster approaches and embedding methodologies, and use automatic coding techniques to implement the new methods. These methods can be applied to various molecular or model systems, with strongly and weakly correlated electrons, to calculate ground and excited state properties and to predict or explain experimental findings.

Our interdisciplinary research group explores how to teach crystals tricks of living matter by investigating dynamic features of molecular framework materials such as metal-organic and covalent organic frameworks (MOFs and COFs). By specifically tuning the structural topology of the framework, we create soft porous crystals which exhibit pore contraction and/or expansion as a response to the adsorption of gases and fluids or external triggers such as light irradiation. Such materials can act as responsive cargo-release systems, nanoscopic sensors or feature counterintuitive phenomena such as negative gas adsorption. We furthermore construct frameworks which contain molecular machines such as light-driven molecular motors and switches as responsive and intrinsically dynamic building blocks. We aim towards collective operating molecular machines in the solid state which are able to actively transport molecules in the pore space and facilitate dynamic conversion and storage of energy carriers and other small molecules. Our diverse team uses a wide range of synthetic and experimental tools and collaborates in national and international research projects to push the boundaries of dynamic features in crystalline solids.

My research interests deal with the design, synthesis and characterization of novel liquid crystalline materials, hybrid materials of dyes and liquid crystals, as well as biomaterials. We try to understand structure property relationships in such materials towards novel organic electronics, ion conductors and battery materials.

The research in my group is mainly focused on non-equilibrium phenomena in Quantum Materials as well as on novel Josephson and Proximity effects using triplet superconductors. One major direction of our actual investigations are Higgs oscillations in superconductors under non-equilibrium conditions. Employing various non-equilibrium techniques we have predicted unique effects that provide novel insights into unconventional superconductors. We collaborate with many experimental groups in Stuttgart as well as in Toyko and Vancouver within the framwork on the Max Planck--UBC--UTokyo Center for Quantum Materials. With the prediction of novel and Josephson and Proximity effects in triplet junctions my group has opened a new field of research in condensed matter physics. Finally, I pioneered a new field 'Higgs spectroscopy' where collective modes of the superconducting order parameter classifies the ground state. A new field in the area of superconductivity. Experiments have confirmed our recent predictions.

The work focuses on synthesis and detailed characterization of metal-rich compounds, preferentially containing nitrogen as a constituent. First emphasis is the design and development of preparative techniques as basis for synthesis of novel materials. Special attention is granted to structural characterization, electronic and magnetic properties as well as mechanical and chemical behavior. These data are inevitable for any detailed consideration of chemical bonding and potential applications. • Advanced solid state synthesis of functional materials including various high pressure techniques, solvothermal synthesis and crystal growth, high temperature synthesis • Solid state reaction pathways and crystal growth mechanisms • Magnetic and superconducting materials, ionic conductors

Our research deals with the theoretical description of the emergent collective phenomena that arise in interacting quantum many-body systems, resulting from competing interactions, disorder, and topology. More specifically, we are interested in unconventional and topological superconductivity, complex phase diagrams, the impact of impurities in crystals, spin-orbit coupling, magnetism, spin liquids and topological order, moiré superlattice systems, non-Hermitian many-body physics, and more. To address these problems, we use a combination of analytical and numerical techniques of quantum field theory and statistical mechanics. Furthermore, we explore the potential of machine-learning to address problems of many-body physics.

Among the possible systems that exhibit quantum properties, molecular spin qubits (MSQs) are one of the most versatile platforms. At the heart of MSQs is the electronic spin, which can originate from unpaired electrons of organic centers, transition metals or lanthanides. The organic ligand surrounding the qubit can also be engineered to tune the electronic and spin properties. My group focuses on the deposition of MSQs on surfaces and investigation using spectroscopic techniques, in particular magnetic resonance. We also aim to extend the operating frequency range from X-band (9 GHz) to THz (> 100 GHz) using plasmonic metasurface magnetic resonators designed and fabricated by us. The group is therefore very multidisciplinary, at the interface of chemistry and physics, and young, having been established in January 2024