| Research Abstract |
We made metal nanowires in ultra-high-vacuum electron microscope to study the structues of nanowires. In addition, we made computer simulation of the high-resolution electron microscope images of metal nanowires. Also we investigated relationship between the structure and conductance of the nanowires. We found for gold nanowires that the gold nanowires exhibit specific structure that is different from the crystaline structure. The new structures had co-axial tube structure, similar to carbon nanotubes. The gold tube, however, consists of the triangular network, dissimilar to graphite sheet of the carbon nanotubes. The structure of gold nanowires, then, expected to have the magic number that determine the stable structure of the nanowire. We found the magic number of the outer-most tube is 7, 11, 13, 14 for the fine nanotubes. The finest nanowire is a single atomic row, of a linear chain of atoms. We found that gold atoms could form a suspended single row chain, with a large bond length of 4A. We simulated the image of gold chain, and verified that the chain has no glue atoms between the 4A separated gold atoms.
In summary, we found gold nanowires have co-axial tube structure, and a single chain has even 4A bond length before its break. Conductance of these specific nanowires, however, have remained to be investigated in future.
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