Electronic control of single-molecule dynamics.
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Biomedical subjects
Publications and source records attributed to Gérald Dujardin.
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We have studied the adsorption of the polyaromatic molecule 1,4"-paratriphenyldimethylacetone, which we have nicknamed Trima. The originality of this linear molecule is that it was designed and synthesized to have two functionalities. First, chemisorb itself to the surface by its two ends rather like a bridge. Second, the central part of the molecule could then be rotated by injecting electrons with the tip of the scanning tunneling microscope (STM). The length of the molecule corresponds exactly to the spacing between five dimers in a row on the Si(100)-2 x 1 surface. We found that the molecule adsorbs as expected on the clean silicon surface by using complementary STM and synchrotron radiation studies. Manipulation of individual molecules with the STM tip showed selective internal modifications that were highly voltage dependent. These manipulations were found to be compatible with an electronic excitation of the pi-pi* transition of the molecule.
The elastic electronic channels through a single hydrogen atom adsorbed on a Ge(111)-c(2 x 8) surface have been investigated by scanning tunneling microscopy and I(V) spectroscopy, whereas inelastic channels have been probed by the vertical and horizontal manipulation of individual hydrogen atoms. The substrate temperature, over the range 30-300 K, has proven to be a powerful parameter to freeze specific electronic channels, offering the possible control of elastic and inelastic channels through a single atom. This opens up very interesting perspectives for controlling the operation of nanodevices.