Direct Observation of the Tunneling Channels of a Chemisorbed Molecule

ABSTRACT Weexploit several scanning tunnelingmicroscopy (STM) techniques, such as atom manipulated scans and constant-height scans, to atomically resolve the adsorption geometry of isolated cobalt-phthalocyanine (CoPc) molecules on a copper (111) surface and to obtain proper low-temperature maps of the molecular conductance. By comparing these crucial findings to density functional calcula-tions, we then provide fresh insight into the CoPc-metal interface. This innovative STM study should be applicable to a wide variety of molecules relevant for mole-cular electronics. SECTION Surfaces, Interfaces, Catalysis U nderstanding electron transport in hybrid metal-organic devices is fundamental to the emerging tech-nology of molecular electronics.1 Functional mole-cules are in factbound to replacediodes, transistors, andswitches to answer the multiple tasks of electronic circuits. Phthalo-cyanine (Pc) and porphyrin derivatives have been most stu-died in this context, also because of their potential interest for spin-dependent electronics,2,3 and optoelectronics.4 The con