Silicon Ring Strain Creates High-Conductance Pathways in Single-Molecule Circuits

Here
we demonstrate for the first time that strained silanes couple
directly to gold electrodes in break-junction conductance measurements.
We find that strained silicon molecular wires terminated by alkyl
sulfide aurophiles behave effectively as single-molecule parallel
circuits with competing sulfur-to-sulfur (low G)
and sulfur-to-silacycle (high G) pathways. We can
switch off the high conducting sulfur-to-silacycle pathway by altering
the environment of the electrode surface to disable the Au–silacycle
coupling. Additionally, we can switch between conductive pathways
in a single molecular junction by modulating the tip–substrate
electrode distance. This study provides a new molecular design to
control electronics in silicon-based single molecule wires.