IV Physical Institute - Wenderoth group

The miniaturization of future electronic devices is intimately connected with the ability to analyze the system on the atomic scale. This requires more than just knowing the local defect structure and the electronic properties, but it has to include the characterization of transport fields and dynamic processes of single defects. Scanning Probe Microscopy (SPM) has opened up a way to access surface as well as bulk properties. Our group is applying and developing SPM tools for challenging questions of fundamental research in this field investigating e.g. metalsemiconductor interfaces, transport in graphene, charge dynamics of single dopants in GaAs, Kondo effect and material classes like pnictides, hexaborides and iridates 

Magnetotransport on the Nanoscale

Setting up a new Scanning Tunneling Microscope equipped with a 7 T magnet we have studied the tranport in graphene down to the nanometer scale. The results have been published in Nature Communications.


Small and fast - Pulsed optical excitation combined with STM

The key elements in the steady miniaturization process of cutting-edge semiconductor devices are the understanding and controlling of charge dynamics on the atomic scale. In detail, we address the study of charging processes of individual doping atoms and, especially, the interaction of those atoms with their surroundings. We use pulsed optical excitation in combination with scanning tunneling microscopy at the n-doped gallium arsenide [GaAs(110)] surface to investigate single donor dynamics within a nanoscaled, localized space charge region. Tuning the tunnel rate can drive the system into nonequilibrium conditions, allowing distinction between the decay of optically induced free charge carriers and the decay of donor charge states. The latter process is atomically resolved and discussed with respect to donor-level binding energies and local donor configurations.