拓扑石墨烯电极分子器件输运特性

利用密度泛函理论结合非平衡格林函数方法，研究了不同拓扑能带结构的石墨烯电极分子器件输运特性.结果表明器件导通电压与电极禁带宽度正相关，同时器件在输运过程中表现出负微分电阻特性，峰谷电流比可达2697.分析认为器件导通源自于偏压升高过程中两电极能带匹配.器件负微分电阻特性源自于偏压升高过程中两电极能带交错.散射态分析表明，能带匹配后散射态分布较为离域，有利于电子通过器件.能带交错后散射态局域于电极处，表明电子输运受到抑制.

Transport properties of molecular devices with topological graphene electrodes

Through the combination of density functional theory with the non-equilibrium Green''s function, the influence of topological energy band structures on graphene electrode molecular devices are explored in this article. The results reveal that the on-voltage of the devices are correlated with the band gap of two electrodes. Moreover, the devices exhibit negative differential resistance characteristics during the transportation process, where the peak-to-valley current ratio reaches 2697. The analysis of results indicated that the conduction of the devices originates from the energy band matching of two electrodes during the increase of the bias voltage, and the negative differential resistance characteristics of the devices come from the mismatch of the energy bands of two electrodes. In addition, through the scattering states analysis, the distributions of scattering states are relatively delocalized when energy bands matches, facilitating electrons to pass through the devices. And the scattering states are localized at the electrode when energy bands mismatches, indicating that the electrons transport are suppressed.