Department of Chemistry, Graduate School of Science and Engineering, Tokyo Institute of Technology, Ookayama, Meguro-ku, Tokyo, Japan.
Nanotechnology. 2013 Aug 9;24(31):315201. doi: 10.1088/0957-4484/24/31/315201. Epub 2013 Jul 12.
We report the fabrication of a highly conductive single pyrazine molecular junction with Pt leads. Mechanically controllable break-junction measurements at low temperatures show two distinct high and low conductance states. These conductance values are two orders of magnitude larger than those of a conventional single molecular junction with anchoring groups because of direct binding of the π conjugated molecule to a metal electrode with large density of states at the Fermi energy. Inelastic electron tunneling spectroscopy combined with density functional theory calculations highlights the vibration modes of the system for the two regimes. Theory allows us to assign the high and low conductance states of the molecular junction to two configurations in which the pyrazine axis is tilted and parallel with respect to the junction axis, respectively. Finally, we show that the pyrazine junction can be reversibly switched between the two bi-stable conductance states by mechanically stretching and relaxing the junction.
我们报告了一种具有 Pt 引线的高导电性单吡嗪分子结的制造。低温下的机械可控断结测量显示出两种明显的高导和低导状态。这些电导值比具有锚固基团的传统单分子结大两个数量级，因为π共轭分子直接与费米能级处具有高密度态的金属电极结合。非弹性电子隧穿光谱结合密度泛函理论计算突出了两个体系的振动模式。理论允许我们将分子结的高导和低导状态分配给吡嗪轴相对于结轴倾斜和平行的两种构型。最后，我们表明通过机械拉伸和放松结，吡嗪结可以在两个双稳态电导状态之间可逆切换。
