García-Suárez V M, Lambert C J
Department of Physics, Lancaster University, Lancaster LA1 4YB, UK.
Nanotechnology. 2008 Nov 12;19(45):455203. doi: 10.1088/0957-4484/19/45/455203. Epub 2008 Oct 8.
We study the electronic and transport properties of two novel molecular wires made of atomic chains of carbon atoms (polyynes) capped with either benzene-thiols or pyridines. While both molecules are structurally similar, the electrical conductance of benzene-thiol-capped chains attached to gold electrodes is found to be much higher than that of pyridine-capped chains. We predict that the conductance is almost independent of molecular length, which suggests that these molecules could be ideal molecular wires for sub-10 nm circuitry. Both systems exhibit negative differential resistance (NDR) but its origin and characteristics depend on the type of molecule. We find a novel type of NDR mechanism produced by the movement of the lowest unoccupied molecular orbital (LUMO) resonance with bias. We also show that by gating the pyridine-capped molecules it is possible to make the NDR disappear and dramatically modify the I-V characteristics and the length dependence.
我们研究了由碳原子原子链（聚炔）制成的两种新型分子线的电学和输运性质，这些聚炔分别用苯硫醇或吡啶封端。虽然这两种分子在结构上相似，但发现连接到金电极的苯硫醇封端链的电导远高于吡啶封端链的电导。我们预测电导几乎与分子长度无关，这表明这些分子可能是用于亚10纳米电路的理想分子线。这两个系统都表现出负微分电阻（NDR），但其起源和特性取决于分子类型。我们发现了一种由最低未占据分子轨道（LUMO）共振随偏压移动产生的新型NDR机制。我们还表明，通过对吡啶封端的分子施加栅极电压，可以使NDR消失，并显著改变I-V特性和长度依赖性。
