Characterization of the molecule bridging nano-link electrodes byusing scanning probe microscope

单分子的电子电导率由于可以控制分子的结构、电子态和官能团而受到人们的关注。尽管进行了深入的研究，但仍有许多问题没有得到解答。在这项研究中，我们试图通过检测由电流引起的分子的振动模式来测量路径。为此，我们采用扫描隧道显微镜（STM）设置，其中衬底金属表面是一个电极，STM尖端是另一个电极。结果表明，该方法可以检测到烷烃硫醇分子几乎完整的振动信号。将计算结果与密度泛函计算结果进行了比较，结果吻合较好。此外，我们还发现有一部分电流在相邻的分子之间跳跃，而不是局限于从一个电极到另一个电极的单个分子。

Electron conductance through a single molecule has attracted attentions because it is possible to control structures, electronic states and functional groups of the molecules. In spite of intensive studies, there are many questions left unanswered. In this study, we tried to measure the path by detecting vibrational modes of the molecules which are caused by the current. We employed scanning tunneling microscope (STM) setting for this purpose, in which the substrate metal surface is an electrode and the STM-tip is the other electrode. The results showed that almost complete vibrational signals of the alkanethiol molecule can be detected. The result was compared with a density-functional calculation, which shows an excellent agreement. In addition, we have found that a certain portion of the current are hopping between neighboring molecules, instead of confined in a single molecule from one electrode to the other.