We have determined the number of transport channels and the value of the transmission coefficients of a single molecular junction by measuring the multiple Andreev reflections (MARs) with a scanning tunneling microscope (STM). By precisely positioning a Nb STM tip to a single C60 molecule on Pb(111), a single molecular junction was fabricated in which the C60 molecule connects with the two superconducting electrodes. From the subharmonic gap structures arising from MARs in the current-voltage characteristics together with the tunneling spectrum of the C60 molecule, we found that unoccupied molecular orbitals of C60 extending to the Fermi level provide three electronic transport channels in the molecular junction. We also found that the transmission coefficients depend on the contact geometry of the molecule. These results demonstrate that the combination of the STM imaging with the MARs measurement provides an effective path for investigating the electronic transport properties through a single molecule sandwiched by two superconducting electrodes.
|Journal||Physical Review B - Condensed Matter and Materials Physics|
|Publication status||Published - 2014 Dec 2|
ASJC Scopus subject areas
- Electronic, Optical and Magnetic Materials
- Condensed Matter Physics