The mission of our Working Group "Methods for Characterization of Transport Phenomena in Energy Materials" (EM-AMCT) is to apply neutron and photon scattering techniques to investigate the dynamic interplay of quasi-particle and charge transport in novel materials for energy conversion. A particular research focus is the study of highly efficient thermoelectric materials. We investigate structure-property relationships bridging from microscopic structure and dynamics to macroscopic thermoelectric properties. Basic research on the interaction processes at the level of elementary excitations in the solid state and thus access to the meV to µeV energy resolution scale is key to a fundamental understanding of transport phenomena in any solid. This knowledge in turn is a necessary prerequisite for optimized design strategies for materials with low thermal conductivity but high electrical conductivity and thermopower. The suppression of phonon propagation on all length scales ranging from interatomic distances in crystalline structures to the nanoscale responsible for reducing thermal conductivity is the overarching theme of our research.
The Working Group operates the neutron three-axis spectrometer FLEXX as the major tool for spectroscopy of low-energy elementary excitations, both for in-house research on energy materials within the Helmholtz program “Energy Efficiency, Materials and Resources (EMR)”, and for the international user community. A further emphasis in the Working Group is to provide innovation in instrumentation for materials’ characterization exploiting inelastic photon scattering. For this purpose, the RIXS spectrometer PEAXIS has been built at the third generation synchrotron source BESSY II. On the Lise-Meitner-Campus in Wannsee, two new laboratories for the characterization and synthesis of thermoelectric compounds have been established.