Regensburg 2019 – wissenschaftliches Programm

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O: Fachverband Oberflächenphysik

O 10: New Methods and Developments II: Scanning Probe, Spectroscopic, and Diffraction Techniques

O 10.4: Vortrag

Montag, 1. April 2019, 15:45–16:00, H3

Vibrational lifetime of a single adsorbed molecule from IETS with superconductive tips — •Angelo Peronio, Marco Weiß, and Franz J. Giessibl — Institut für Experimentelle und Angewandte Physik, Universität Regensburg, 93040 Regensburg, Germany

Inelastic electron tunnelling spectroscopy with a scanning tunnelling microscope (STM-IETS) enables the measurement of excitations with atomic spatial resolution, such as vibrational and rotational modes of single molecules, and flip of single spins. The intrinsic lineshape of molecular vibrations encodes the coupling between the vibrational mode of interest and the surrounding environment, but the measured lineshape is usually dominated by extrinsic effects, such as temperature, modulation, and bias noise broadening. The temperature broadening originates form the finite width of the Fermi edge of the electronic density of states of the tip apex. We circumvent the temperature broadening by using the gap of a superconductive STM tip to probe the vibrational modes of carbon monoxide adsorbed on copper. By deconvolving the density of electronic states of the tip from the resulting spectra, we determine the intrinsic vibrational density of states and the lifetime of the vibrational excited state.