Severing - Local Electronic Structure of f electron materials

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.

Heavy-fermion compounds are fascinating materials that raise fundamental questions in the field of strongly correlated matter. Their physical properties are driven by the hybridization of the atomic-like f electrons with those of the conduction band (cf-hybridization). Unconventional superconductivity, Kondo insulating behaviour together with putative strongly correlated topology, or hidden order are some of the intriguing phenomena to be investigated. The group applies state-of-the-art synchrotron-based methods such as x-ray absorption (XAS), non-resonant inelastic x-ray scattering (NIXS) in the beyond dipole limit, resonant inelastic x-ray scattering (RIXS), and photoelectron spectroscopy with hard x-rays (HAXPES) to investigate the symmetry of the ground state, the low energy excitations, as well as the itinerant aspects of the entangled ground state.

More recently, special focus is put on uranium based compounds where we investigate the dual nature of f electrons. Here NIXS experiments that are performed at the MPI beamline P01 at PETRA_III/DESY in Hamburg provide unprecedented insight into the U ground state symmetry. Explorative work for actually measuring ff excitations also in uranium intermetallic compounds are on their way.