Research Activities

Spectroscopy is applied in a wide variety of scientific disciplines to explore matter's electronic structure. We employ synchrotron-based spectroscopic techniques such as Angle-Resolved PhotoEmission Spectroscopy (ARPES), Hard X-ray PhotoEmission Spectroscopy (HAXPES), Resonant X-ray Scattering (RXS), Non-resonant Inelastic  X-ray Scattering (NIXS), and X-ray Absorption Spectroscopy (XAS).

The focus of our research are materials in thin film form, especially transition metal and rare-earth oxides as well as topological insulator compounds. Our state-of-art in-house ultra-high vacuum system consists of two molecular beam epitaxy chambers and five facilities for an in-situ characterization of the samples, including electron diffraction techniques (RHEED, LEED), photoelectron spectroscopy (XPS, ARPES), temperature-dependent resistivity measurements, and ionic liquid gating experiments.

Our research focuses on the investigation of electronic correlations by means of Scanning Tunneling Microscopy/Spectroscopy, electronic transport and magnetic measurements of bulk and thin film samples.  The materials and phenomena of interest include 4f heavy fermion systems, superconductivity, electronic inhomogeneity, two-dimensional transport and non-trivial topological surface states.

The study of exciting physical properties within the quantum mechanical world of condensed matter physics starts with the synthesis of single crystals. 
For the study of the nuclear structure of our synthesized materials as well as their spin structure and emergent spin excitation spectra X-ray and neutron scattering experiments can be performed e.g. in synchrotrons or spallation / reactor neutron sources.

Our research focuses on the study of the critical dynamics and the static properties of strongly correlated electron materials using scattering methods.
Among others our studies include systems close to quantum criticality, geometric frustration in magnetic metals, spin-density-wave and charge- density-wave compounds, unconventional superconductors, etc.
 

We investigate the local electronic structure of f electron materials with synchrotron based methods. In particular, we are interested in the orbital occupation of the f states in rare earth or uranium heavy fermion compounds in order to obtain a deeper insight into the hybridization mechanisms with the conduction bands.

Theoretical work is focused on the effect of electronic correlations on quasiparticle renormalization in f-electron compounds and appearance of broken symmetries.