  We study electron transport through single-molecule junctions formed by an
octanethiol molecule bonded with the thiol anchoring group to a gold electrode
and the opposing methyl endgroup to a carbon tip. Using the scanning tunneling
microscope based break junction technique, we measure the electrical
conductance of such molecular junctions. We observe the presence of
well-defined conductance plateaus during the stretching of the molecular
bridge, which is the signature of the formation of a molecular junction.
