Supramolecular Nanorings for Exploring Quantum Interference

杨格在1803年著名的双缝实验证明了光的行为就像波。从狭缝中射出的光具有一种独特的强度模式，该模式源于相长干涉和相消干涉。后来人们发现，当单个粒子(光子甚至分子)通过双缝时，它们会产生类似的干涉图案；这个实验成为波粒二元性的关键证据。马赫-赞德干涉仪类似于杨的双缝装置，不同的是光被分成两条路径。当光重新组合时，会发生相长干涉或相消干涉，具体取决于来自两条路径的光的相位不同。路径长度或折射率的细微差异很容易被检测到，因为它们决定了相位差异，从而控制了干扰。该项目旨在合成和测试由具有两个电荷传输路径的分子组成的“分子马赫-曾德干涉仪”；两个传输通道之间的干扰控制整个系统是导电(同相)还是不导电(异相)。因此，这些分子有望对磁场或电场敏感，这些磁场或电场可以改变两个通道的相对相位。此外，量子干涉效应往往会导致电子能量在传输过程中发生急剧变化，这可能会导致强烈的热电效应。这个项目致力于探索基本原理，但从长远来看，这项研究有可能产生商业颠覆性技术，如用于清除热能的热电设备，以及功率要求更低、开关突然和占地面积小的晶体管。这个项目如果是三个研究小组的彻底整合合作，专注于(1)牛津：分子结构的设计和合成，(2)利物浦：单分子电导和热电势的测试，以及(3)兰开斯特：理论和计算模拟，以指导对实验数据的解释，目前，电子束光刻等自上而下的15纳米长度范围和化学合成等自下而上的技术之间存在着无人区。这个项目中研究的分子直径为3纳米，但可以增加到10纳米左右。因此，该项目是在摩尔定律的限制下，朝着弥合这一关键的技术规模差距迈出的重要一步。

Young's famous double-slit experiment of 1803 demonstrated that light behaves as a wave. The light emerging from the slits has a characteristic intensity pattern originating from constructive and destructive interference. Later it was found that when single particles (photons or even molecules) pass through a double slit they produce similar interference patterns; this experiment became the key piece of evidence for wave-particle duality.A Mach-Zender interferometer is similar to Young's double-slit setup, except that light is split into two routes using mirrors. When the light is recombined, constructive or destructive interference occurs, depending on the difference in the phase of the light from the two routes. Subtle differences in the path-length, or refractive index, can easily be detected, because they determine the phase difference, and thus they control the interference.This project aims to synthesise and test a "molecular Mach-Zender interferometer" consisting of a molecule with two charge-transport paths; interference between the two transmission channels controls whether the whole system is conductive (in phase) or non-conductive (out of phase). Thus these molecules are expected to be sensitive to magnetic or electric fields which can change the relative phases of the two channels. Furthermore quantum interference effects tend to produce sharp changes in transmission with electron energy, which can result in strong thermoelectric effects. This project is concerned with exploring fundamental principles, but in the long term, this research has the potential to generate commercially disruptive technologies, such as thermoelectric devices for scavenging thermal energy, and transistors with reduced power requirements, abrupt switching and small footprints.This project if a thoroughly integrated collaboration of three research groups focusing on (1) Oxford: design and synthesis of molecular structures, (2) Liverpool: testing of single molecule conductance and thermopower, and (3) Lancaster: theory and computational simulation, to guide the interpretation of the experimental data, and the design of new molecular structures.At present there exists a no-man's land between the 15-nm length scale accessible to top-down technologies, such as electron-beam lithography, and bottom-up technologies such as chemical synthesis. The molecules investigated in this project are 3 nm across, but can be increased in size up to around 10 nm. This project is therefore a significant step towards bridging this crucial technology-scale gap, at the limit of Moore's law.