【作者】 侯士敏；

【Author】 Shimin Hou;Department of Electronic, Peking University;

【机构】 北京大学信息科学技术学院；

【摘要】 转变电压谱是一种表征分子电子器件中的分子能级位置的重要谱学方法,我们利用非平衡格林函数与密度泛函理论相结合方法研究了金电极真空隧道结和分子结的转变电压特性。计算结果表明,金电极真空隧道结的转变电压决定于电极表面原子级突起6p原子轨道的局域态密度,而不是电极之间的真空势垒形状。对于金电极与巯基共轭分子形成的分子结,其转变电压决定于巯基共轭分子的最高占据轨道;但是,对于金电极与巯基饱和烷烃分子形成的分子结,其转变电压则决定于分子-电极界面的Au-S成键态。更多还原

【Abstract】 Transition voltage spectroscopy is an important spectroscopic tool characterizing molecular electronic devices. The transition voltages of vacuum-spaced and molecular junctions with gold electrodes are investigated by employing the non-equilibrium Green’s function formalism combined with density functional theory. Our calculations show that the transition voltages of gold-vacuum-gold tunneling junctions are determined by the local density of states of the apex gold atom on the electrode surface rather than by the vacuum barrier shape. For Au-poly(phenylene) thiol-Au molecular junctions, their transition voltages are dominated by the highest occupied molecular orbital. In contrast, the transition voltage of Au–alkanedithiol–Au junctions is directly related to the Au–S bonds localized at the molecule–electrode interfaces.更多还原