Effects of electron-phonon coupling on quantum interference in polyenes.
Effects of electron-phonon coupling on quantum interference in polyenes.
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DOI：
10.1063/1.5048955
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发表时间：
2018-10
期刊：
影响因子：
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通讯作者：
Yuta Tsuji;K. Yoshizawa
中科院分区：
文献类型：
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作者：
Yuta Tsuji;K. Yoshizawa
当量子干涉发生在π共轭分子组成的单分子结中时，π-电子的弹性透射被阻断，而σ-电子的弹性透射保持不变。当涉及到非弹性输运时，被困在两个金属电极之间的电子通过电子-声子耦合而失去能量，振动是否影响QI特征并不一定明显。在本文中，在h<s:1> ckel/紧密结合模型的基础上，我们解决了通过线性和环状多烯的非弹性传输，这些多烯被条件限制为显示QI。用分子图邻接矩阵的负逆近似的零阶格林函数与自洽玻恩近似的最低阶展开结合使用。由于模型的简化，只发现π-to-π散射的适用性有限。只有拓扑方面的减相包括在内。在这种理论结构中，π共轭分子的交替性质有助于根据原子位宇称对消相模式进行分类。提出了一个规则，即当星形原子和非星形原子都与电极连接时，QI总是发生，并且与电极连接的原子属于不同部集的原子有助于非弹性π到π散射。如果QI发生在星形原子和非星形原子与电极连接时，则非弹性π -π散射对输运的贡献预计不重要。
It has been well accepted that when quantum interference (QI) occurs in a single molecular junction comprised of a π-conjugated molecule, the elastic π-electron transmission is blocked, while the elastic σ-electron transmission remains unchanged. When it comes to inelastic transport, in which passing electrons across the molecule trapped in between two metallic electrodes lose their energy through electron-phonon coupling, it is not necessarily obvious whether vibration affects the QI feature or not. In this paper, on the basis of a Hückel/tight-binding model, we address the inelastic transport through linear and cyclic polyenes which are conditioned to show QI. The zeroth-order Green's function approximated by the negative inverse of the adjacency matrix of a molecular graph is used in conjunction with the lowest order expansion of the self-consistent Born approximation. Owing to the simplification of the model, it just finds the limited applicability for the π-to-π scattering. Only topological aspects of dephasing are included. In such a theoretical construct, the alternant nature of the π-conjugated molecule is found helpful for classifying the dephasing patterns based on the parity of atomic sites. A rule is proposed, and it says that when both starred or both unstarred atoms are connected with the electrodes, QI always occurs, and atoms which belong to a different partite set from that of the atoms connected with the electrodes contribute to the inelastic π-to-π scattering. If QI occurs when a starred atom and an unstarred atom are connected with the electrodes, the contribution of the inelastic π-to-π scattering to the transport is expected to be unimportant.