Our group focusses on the electronic structure of correlated systems in various forms, e.g. transition metal oxides (TMO's), high-TC superconductors and other low-dimensional systems like organic systems and nanowires on semiconductor substrates. Special interest lies in the interplay of different degrees of freedom (charge, spin, orbital, lattice) in the light of metal-insulator and other phase transitions. Complementary research is performed in the field of dilute magnetic semiconductors, esp. GaMnAs. Recently, we also started to investigate oxide heterostructure materials.
The main experimental method is photoemission spectroscopy (PES) with excitation energies ranging from the ultraviolet (UPS) to the intermediate-energy x-ray regime (XPS) and even up to hard x-ray energies of several keV (HAXPES).
Our laboratory includes a system for pulsed laser deposition for the fabrication of thin films (only few unit cells thick), an Omicron ESCA-system with an E125 hemispherical analyser, a Specs Phoibos 100 with CCD detector, an Omicron VT-STM, LEED, 30 kV high pressure RHEED, cryostats for transport measurements and others.
In order to perform angle-resolved photoemission (ARPES) with ultimate resolution we also use synchrotron light sources around the world, e.g., Diamond (UK), SLS (Switzerland), ALS (USA), or SPring-8 (Japan). At the PETRA-III storage ring of DESY (Hamburg, Germany) we operate our own endstation for HAXPES and are involved in the development of a spin-resolved k-space-microscope using the time-of-flight method for the investigation of magnetic systems like magnetite.
k- and spin-resolved time-of-flight microscopy using hard and soft x-rays:
- Hard x-ray beamline P22 at Deutsches Elektronen-Synchrotron DESY in Hamburg
- Hard/Soft x-ray beamline I09 at Diamond Light Source in Didcot, UK
- AG Prof. Schönhense at Johannes Gutenberg-Universität in Mainz
Advanced Methods of Electron Microscopy:
Find here all theses work done in our group (PhD, Diploma/Master, Bachelor theses)