Mechanismus of vibrational assisted electronic transport through single paraphenyl molecules investigated by electron and light sprectroscopy

本项目旨在将单分子隧道谱研究与单分子结电子输运研究相结合，利用低温扫描隧道显微镜（STM）针尖接触单分子，研究导致铅分子-铅结形成的步骤。我们将研究由氨基，吡啶和腈分子端基的孤对电子与氧功能化铜表面和硅表面的原子悬挂键之间的配价键形成的稳定的分子电极接触。我们研究i）隧道制度，使用隧道光谱学（弹性和非弹性），以揭示结构，电子配置和声子结构，ii）高电导制度，以遵循过渡到接触和分子共振向导电带的演变，和iii）接触制度，以确定运输机制（弹性与非弹性，相干与有序）及其与分子和接触结构的关系。我们的目标是提供良好表征系统的可再现传输（电导-电压）特性，然后可以与SPP 1243中的理论合作伙伴合作进行分析，以回答以下问题：在电荷传输中引线电子配置的作用是什么？分子轨道是如何从局域共振和振动演化到输运带和声子的？我们能在分子结中看到电子封锁效应吗？能量在分子中是如何耗散的？

This project aims at bridging the research on single molecule tunnelling spectroscopy with research on electron transport through single-molecule junctions by using a low temperature scanning tunnelling microscope (STM) tip to approach to contact a single molecule, investigating the steps leading to the formation of a leadmolecule- lead junction. We will investigate stable molecule-electrode contacts formed by dative bonds between lone-pair electrons of amino, pyridine and nitrile molecular end-groups with oxygen functionalised copper surfaces and with atomic dangling bonds of silicon surfaces. We study i) the tunnel regime, using tunnel spectroscopy (elastic and inelastic) to reveal structure, electronic configuration and phonon structure, ii) the high conductance regime, to follow the transition to contact and the evolution of molecular resonances toward conducting bands, and iii) the contact regime, to identify transport mechanisms (elastic vs. inelastic, coherent vs. sequential) and their relation with molecular and contact structure. The goal is to provide reproducible transport (conductance-voltage) characteristics of well characterised systems, which can be then analysed in collaboration with theoretical partners in the SPP 1243 to answer the following questions: Which is the role of the leads electronic configuration in the charge transport? How do molecular orbitals evolve from local resonances and vibrations to transport bands and phonons? Can we see an electronic blockade effect in molecular junctions? How is energy dissipated in the molecule?