Regensburg 2007 – wissenschaftliches Programm
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TT: Fachverband Tiefe Temperaturen
TT 28: Transport - Poster Session
TT 28.10: Poster
Donnerstag, 29. März 2007, 14:00–17:45, Poster A
Conductivity through single Ferrocenedithiol molecules — •Jedrzej Schmeidel1, Gernot Gardinowski1, Herbert Pfnür1, Christoph Tegenkamp1, Volodymyr Maslyuk2, Ingrid Mertig2, and Mads Brandbyge3 — 1Institut für Festkörperphysik, Leibniz-Universität Hannover, 30167 Hannover, Germany — 2Theoretische Physik, Martin-Luther-Universität Halle-Wittenberg , 06099 Halle, Germany — 3Mikroelektronik Centret, Technical University of Denmark, Kongens Lyngby, Denmark
We have investigated systematically the fabrication and characterization of metallic nanometer–sized(nm) gaps suitable for conductivity measurements of single molecules. Epitaxially grown Ag nanostructures with a thickness down to 10 monolayers on Si(100) were used for a controlled gap formation by electromigration (EM). The gaps obtained range from several nm down to sub–nm, as revealed by lateral conductivity measurements and by scanning tunneling microscopy done under ultra high vacuum conditions. After adsorption of a single ferrocenedithiol (FDT) molecule in between the gap by self-assembly the zero bias resistance is around 40kOhm. In addition, the dI/dV curve shows molecular contributions which can be attributed to ferrocene induced states near the Fermi edge. In particular, the zero bias resistance is calculated correctly using the TRANSIESTA code. As pre-optimized structures for transport calcuations, the adsorption parameters obtained from VASP are used, assuming a thiolate bound configuration of one molecule in between defect-free Ag contacts.