Heather L. Tierney, Colin J. Murphy, April D. Jewell, Ashleigh
E. Baber, Erin V. Iski, Harout Y. Khodaverdian, Allister F.
McGuire, Nikolai Klebanov, and E. Charles H. Sykes
For molecules to be used as components in molecular machines, methods
that couple individual molecules to external energy sources and that
selectively excite motion in a given direction are required. Significant
progress has been made in the construction of molecular motors powered by
light and by chemical reactions, but electrically driven motors have not
yet been built, despite several theoretical proposals for such motors. Here we
report that a butyl methyl sulphide molecule adsorbed on a copper surface can
be operated as a single-molecule electric motor. Electrons from a scanning
tunnelling microscope are used to drive the directional motion of the molecule
in a two-terminal setup. Moreover, the temperature and electron flux can be
adjusted to allow each rotational event to be monitored at the molecular scale
in real time. The direction and rate of the rotation are related to the chiralities
of both the molecule and the tip of the microscope (which serves as the
electrode), illustrating the importance of the symmetry of the metal contacts
in atomic-scale electrical devices.
Journal: Nature Nanotechnology
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