Regensburg 2019 – wissenschaftliches Programm
O 71.3: Poster
Mittwoch, 3. April 2019, 17:45–20:00, Poster B2
A confined hydrogen molecule chopping light emission from a tunnel junction — Pablo Merino1,2,3, Anna Rosławska1, Christopher C. Leon1, Christoph Große1, César González4, •Klaus Kuhnke1, and Klaus Kern1,5 — 1Max-Planck-Institut für Festkörperforschung, Stuttgart, Germany — 2Instituto de Ciencia de Materiales de Madrid, Spain — 3Instituto de Física Fundamental, Madrid, Spain — 4Departamento de Física Teorica de la Materia Condensada, Madrid, Spain — 5École Polytechnique Fédérale de Lausanne, Switzerland
We combine scanning tunneling microscopy (STM) with optical correlation spectroscopy to access the dynamics of H2/Au(111). At low coverage (ca. 2%) molecular hydrogen forms a hexagonal superlattice with a large intermolecular spacing of 2 nm ascribed to molecular interaction dominated by surface state electrons at the Fermi energy. We characterize this yet unexplored glassy phase which provides an open structure in which a single molecule is confined - yet free to move in and out of the tunnel junction. Plasmonic light emission from the STM junction in constant height mode is employed to observe this motion by means of the resulting intensity modulation. Analyzing the time-resolved photon train detected in the far-field provides an autocorrelation function g(2)(Δ t) which is dominated by one exponential. The residence time in the junction (10 ms) and the out-of-junction excursion time (3 ms) are obtained by modeling the system with a two-state (in-junction ⇔ out-of-junction) rate equation model.