Würzburg ToCoTronics Colloquium

Using low-temperature scanning tunneling microscopy and occasionally synchrotron radiation methods we investigate molecules at surfaces. The experiments along with model calculations reveal molecular spin states and electron transport properties as well as intermolecular interactions. This talk will address spin related phenomena such as spin-state switching in spin-crossover compounds. We further demonstrate that diamagnetic molecules can acquire a spin when they are arranged into suitable supramolecules on superconducting Pb. As a consequence, sharp resonances develop in the superconductor gap. We harness them to enhance inelastic tunneling spectroscopy of molecular vibrations. This new methods drastically enhances the sensitivity and also improves the energy resolution beyond the thermal broadening limit. Finally, and somewhat unrelated, the conductance anomaly observed from Co atoms on Cu(111) will be discussed. Our data from long atomic chains suggest that the anomaly is not due to a Kondo resonance, in contrast to earlier interpretations.

Work done in collaboration with Jan Homberg, Alexander Weismann, Manuel Gruber, Troels Markussen, Sven Johannsen, Sascha Schüddekopf, Sascha Ossinger, Jan Grunwald, Alexander Herman, Heiko Wende, Felix Tuczek, Chao Li, Roberto Robles, Nicolas Lorente, Neda Noei, Niklas Ide, Roberto Mozara, Alexander I. Lichtenstein, Ana M. Montero, Sascha Brinker, Filipe S. M. Guimaraes, Samir Lounis.