Shi Xingqiang, Zheng Xiaohong, Dai Zhenxiang, Wang Yang, Zeng Zhi
Key Laboratory of Materials Physics, Institute of Solid State Physics, Chinese Academy of Sciences and Graduate School of the Chinese Academy of Sciences, Hefei 230031, P.R. China.
J Phys Chem B. 2005 Mar 3;109(8):3334-9. doi: 10.1021/jp046349g.
We report a first-principles study of electrical transport and negative differential resistance (NDR) in a single molecular conductor consisting of a borazine ring sandwiched between two Au(100) electrodes with a finite cross section. The projected density of states (PDOS) and transmission coefficients under various external voltage biases are analyzed, and it suggests that the variation of the coupling between the molecule and the electrodes with external bias leads to NDR. Therefore, we propose that one origin of NDR in molecular devices is caused by the characteristics of both the molecule and the electrodes as well as their cooperation, not necessarily only by the inherent properties of certain species of molecules themselves. The changes of charge state of the molecule have minor effects on NDR in this device because the Mulliken population analysis shows that electron occupation variation on the molecule is very small when different external biases are applied.
我们报告了一项关于单分子导体中电输运和负微分电阻（NDR）的第一性原理研究，该单分子导体由夹在两个具有有限横截面的Au(100)电极之间的硼嗪环组成。分析了各种外部电压偏置下的投影态密度（PDOS）和传输系数，结果表明分子与电极之间的耦合随外部偏置的变化导致了NDR。因此，我们提出分子器件中NDR的一个起源是由分子和电极的特性及其协同作用引起的，不一定仅仅是由某些特定种类分子本身的固有性质引起的。在该器件中，分子电荷态的变化对NDR的影响较小，因为穆利肯布居分析表明，施加不同外部偏置时，分子上的电子占据变化非常小。
