Veranstaltungsdetails

21.6.2011, 17:00
Jungiusstr. 11, Hörsaal AP

SFB 668 - Seminar

Prof. Carmen Herrmann (Universität Hamburg):

Charge and spin transport on the molecular scale

Charge and spin transport on the molecular scale is not only a topic of crucial importance for biological processes such as photosynthesis, but has also become highly relevant for nanotechnology, for example for molecular electronics and spintronics. Here, the focus will be on how theory can contribute to the understanding and design of molecular spintronics devices within the coherent tunneling regime. First, we investigate for a set of iron porphyrin molecular junctions to what extent an electron tunnels through the iron atom as opposed to through the ligand, and how the spin state and the connection scheme influence this behavior. Second, we ask what properties of the electronic structure make an organic radical a good spin filter. For both projects, we employ analyses of local (atomic) contributions to the electronic transmission, and of the central subsystem molecular orbitals. We use a combination of density functional theory, Green?s function techniques and the Landauer-Imry-Buttiker approach. The insight gained may be relevant for molecular bridges in a variety of environments, ranging from single- molecule junctions to electron transfer in donor-bridge-acceptor systems to polymeric structures.