Regensburg 2019 – wissenschaftliches Programm
O 47.13: Poster
Dienstag, 2. April 2019, 18:00–20:00, Poster D
Space and time-resolved unidirectional switching of single molecules — •Thomas Buchner, Dominik Peller, Lukas Kastner, Rupert Huber, and Jascha Repp — Department of Physics, University of Regensburg, 93040 Regensburg, Germany
Combining low-temperature scanning tunneling microscopy (STM) and ultrafast lightwave electronics has paved the way for tracking single molecule dynamics with combined atomic resolution and femtosecond temporal precision . Here, we introduce single-shot detection in lightwave STM with single-electron control, opening the door to path-selective studies of unidirectional quantum events. We examine a magnesium phthalocyanine molecule, which adsorbs on sodium chloride in a bistable geometry. By means of single light pulses, single electrons can be deliberately injected into an unoccupied orbital, triggering the molecule to rearrange on the surface, eventually leading to a switching of its adsorption geometry. Monitoring a non-resonant cotunneling current allows one to detect every single switching event. In pump-probe experiments, the quantum yield for switching is measured for various parameters with combined sub-Å spatial and femtosecond temporal precision, which exhibits a distinct behavior for each reaction path. These multi-dimensional experimental data show marked oscillations in time and provide a fingerprint of the atomistic details of the molecular dynamics, at the sub-picosecond time scale.
 T. L. Cocker, D. Peller et al., Nature 539, 263-267 (2016)