Computational Modeling of Spin-bearing Metal-organics and of Lattice Thermal Properties
The access to excellent computer resources has become a key ingredient in modern materials research. In the present proposal we are asking for computer time for two research areas in which we are currently working, which have proven to be the most computationally demanding areas of our research. In the first area we employ state-of-the-art calculations to study the electronic structure, magnetic and structural properties of spin-bearing metal-organic materials and single molecule magnets. Our focus is on large metal-organic molecules, which are well known from life science (for example, the Fe-porphyrin molecule that provides the functionality of hemoglobin). The magnetic properties of such molecules are very interesting. Under properly tuned conditions, spin switching of these molecules can be externally stimulated, which offers the possibility to develop versatile spintronic devices on the basis of metal-organic molecules. We are investigating the possible spin switching of metallo-porphyrins on a metallic surface and in contact with a reagent (e.g., nitric oxide) in order to discover conditions under which the spin can be switched in a molecular electronic device. An emerging research direction is that of single molecule magnets grafted to a magnetic substrate. A further research direction is the ab-initio molecular dynamics description and prediction of spin-crossover systems. In the second area of our research, we perform materials modeling for thermal properties of materials. One of our focusses is to predict the thermal properties of nuclear fuel materials. To predict these from first-principles we have to perform simulations of the lattice dynamics (phonons) and surface vibrations, including as well phonon-phonon interactions to compute phonon lifetimes, from which we then compute the lattice thermal conductivity. A further focus is to treat non-equilibrium interactions between phonons and electrons in materials. Such interactions become important when a material is quickly excited, for example with a short laser pulse in a pump-probe experiment.