基于非对称分子的全碳分子器件的负微分电阻及整流行为

摘要

使用基于非平衡格林函数和密度泛函理论的第一性原理计算方法，研究苯环连接碳链构成的非对称分子与石墨烯电极组成的分子器件的电子输运性质。通过计算，我们发现该分子器件表现出明显的负微分电阻现象和整流行为，通过分析分子自洽哈密顿量和前线分子轨道，发现整流行为的出现是由于不同方向的外加电场导致前线分子轨道能级的非对称移动造成的，而负微分电阻是因为在某些特定电压下电导通道被压制，使得电流迅速降低而形成的。%Using thefirst-principles method,It investigated the electronic transport properties for an novel a-symmetry molecular device constructed by a phenyl ring embedding in a carbon chain between two gra-phene electrodes.Obviouslynegative differential resistance (NDR ) behavior and rectifying performance werenumerically observed in such proposed molecular device.The analysis of the molecularproj ected self-consistent Hamiltonian and the evolution of the frontier molecular orbitals (MOs)suggestedthatthe rectif-ying performance wereresulting from the asymmetry energy level shift of MOs under the differentdirection of the external electric field.But the NDR behavior came from the conduction orbital beingsuppressed at certain bias.