接触构型及电极距离对4,4’-二巯基二苯醚分子电输运性质的影响

利用从头计算方法和弹性散射格林函数的方法,对4,4'-二巯基二苯醚分子电输运特性的研究结果显示,分子与电极之间接触点的构型以及两电极之间的距离对4,4'-二巯基二苯醚分子的电输运性质都有很大影响.电流随电极距离的变化与耦合系数的变化存在着密切关系.分子末端硫原子处于金原子的顶位上时电流的开启电压很小,而处在金(111)面的空位上时约有1.0V左右电流禁区.与实验结果相比,硫原子更可能处在金(111)面的空位上方.

Influence of contact structure and electrodes distance on the electronic transport properties of bis-(4-mercaptophenyl)-ether molecule

Basing on ab initio method and the elastic scattering Green's function theory, we have investigated the electronic transport properties of metal-molecule-metal junctions by taking the bis-(4-mercaptophenyl)-ether molecule as an example. Numerical results show that the contact structure and the electrodes distance have significant effects on the electronic transport properties of the molecular junction. The changes of current and conductance versus electrodes distance have close relationship with the changes of the coupling coefficients. When the terminational sulfur atoms of the molecule sited on the top positions of the gold atoms, the current and conductance curves have small onset bias voltages. There exists current gap of about 1V for the sulfur atoms sitting on the hollow positions of Au(111) surfaces. Compared with the experimental result, it is demonstrated that the terminational sulfur atoms are more likely sited on the hollow positions of Au(111) surfaces.