Regensburg 2007 – wissenschaftliches Programm
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O: Fachverband Oberflächenphysik
O 17: Poster Session I (Nanostructures at Surfaces; Metal Substrates: Epitaxy and Growth; Methods: Scanning Probe Techniques; Phase Transitions)
O 17.17: Poster
Montag, 26. März 2007, 17:30–20:30, Poster C
Spatially resolved eletronic and vibronic characteristics of a single higher diamondoid molecule — Yayu Wang1, •Daniel Wegner1, Xinghua Lu1, Ryan Yamachika1, Andre Wachowiak1, Emmanouil Kioupakis1, Steven Louie1, Mike Crommie1, Jeremy Dahl2, Shenggao Liu2, and Robert Carlson2 — 1Department of Physics, University of California at Berkeley, and Materials Science Division, Lawrence Berkeley National Laboratory, Berkeley, California, USA. — 2MolecularDiamond Technologies, Chevron Technology Ventures, Richmond, CA, USA
Diamondoids are hydrocarbon molecules with diamond-like cage structures. Their structural complexity and chemical bond tunability make them ideal building blocks for creating novel nanostructures. We have investigated the recently discovered higher diamandoids at the single-molecule level using cryogenic scanning tunneling microscopy (STM) and spectroscopy (STS). STM images of individual 121-tetramantane molecules display pronounced nodal features across the molecular surface. Despite a large energy gap auround the Fermi level, STS and IETS reveal strong interactions between tunneling electrons and the diamondoid C-H stretch mode. The strength of the vibronic coupling has a distinct spatial distribution and peaks strongly at the topographic line nodes. Density-functional theory calculations have been used to reproduce the basic electronic structure and the peculiar geometric features of the higher diamondoids.