SKM 2023 – wissenschaftliches Programm

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TT: Fachverband Tiefe Temperaturen

TT 8: Yu-Shiba-Rusinov Systems

TT 8.1: Hauptvortrag

Montag, 27. März 2023, 15:00–15:30, HSZ 103

Molecules on a superconductor: Inducing magnetism and resonance-enhanced vibrational spectroscopy — •Richard Berndt¹, Jan Homberg¹, Alexander Weismann¹, Manuel Gruber², and Troels Markussen³ — ¹Institut für Experimentelle und Angewandte Physik, Christian-Albrechts-Universität zu Kiel, Germany — ²Fakultät für Physik, Universität Duisburg-Essen, Germany — ³Synopsys Denmark, Copenhagen, Denmark

Magnetic impurities can induce so-called Yu-Shiba-Rusinov (YSR) resonances in the energy gap of a superconductor. We use these resonances for spin detection in a scanning tunneling microscope and demonstrate that diamagnetic phthalocyanine molecules acquire a spin when they are arranged into supramolecular arrays on superconducting Pb(100). Spectroscopy and modeling reveal that the electrostatic fields of its neighbors render a molecule paramagnetic.

Inelastic tunneling spectroscopy of vibrational excitations usually suffers from low sensitivity and limited spectral resolution. We harness YSR resonances to enhance the inelastic signal by more than an order of magnitude and to improve the energy resolution beyond the thermal broadening limit. As a result, 46 vibrational peaks are resolved from Pb-phthalocyanine enabling a comparison with calculated modes. The method may help to further probe the interaction of molecules with their environment and to better understand selection rules for vibrational excitations.