FLF renewal

热机是经典热力学的基石之一。通过将热能转化为机械能，它们推动了19世纪的工业革命。分子热机具有将热能转化为电能的潜力，反之亦然，效率接近热力学极限。因此，单分子热电的主题对于芯片上冷却和热电能量收集技术的发展具有根本性的重要性，这些技术可以为21世纪的量子革命提供动力。利用单分子热电能量转换能力的关键挑战是更好地理解分子电子自由度和振动自由度之间的量子力学相互作用，这可能会对开放量子系统研究领域的实验产生革命性的影响。这些实验将在两个方面产生影响：探索新科学和为新技术奠定基础。新科学：分子热机为探索量子力学和热力学之间的对话提供了理想的平台。虽然已经为此进行了一些理论上的努力，但许多预测仍有待实验验证。在分子尺度上对热力学的新见解也将提出进一步的问题：量子相干性是否提高了单分子热机的热电效率？如果玻恩-奥本海默近似失效会发生什么？分子的振动模式能被电冷却到基态吗？新技术：热电技术在提供简单、可靠的发电方面有着悠久的历史。然而，热电材料用于回收废热的使用仍然有限，因为它们的稀缺性和毒性，而且不幸的是，决定其效率的特性——电导率、热传导率和塞贝克系数——是相互矛盾的，这意味着一个的改善会使另一个恶化。单分子热机中的量子效应解除了这些矛盾性质之间的联系，从而为高效热电发电机提供了可能性，这种发电机可以提供一种低成本、环保的方式来清除废热，从而大大降低全球能源消耗。本提案旨在开发仪器和实验方法来研究单个分子中受控热电热-能量转换，其中重点是控制分子相互作用。这种控制将通过使用通过分子连接的纳米颗粒的二维网络来实现。基于最近的突破性实验，我将使用电场控制来调整分子能级与基板费米能级的对齐，同时控制隧道耦合和施加的偏置电压。一个局部加热器将驱动热生成的电子流通过单个分子，由于系统中前所未有的可调性，我将能够对其进行优化。通过在宽参数空间上探测热电效率，我将建立单分子能量转换的内在热力学限制。

Heat engines form one of the cornerstones of classical thermodynamics. By converting heat into mechanical work they powered the industrial revolution in the 19th century. Molecular heat engines have the potential to convert thermal energy to electrical power and vice versa with efficiency close to the thermodynamic limit. The topic of single-molecule thermoelectricity is therefore of fundamental importance for the development of on-chip cooling and heat-to-electricity energy harvesting technologies that could power the quantum revolution of the 21st century. The key challenge in harnessing the thermoelectric energy conversion capabilities of single molecules is gaining a better understanding of the quantum mechanical interactions between molecular electronic and vibrational degrees of freedom, which could prove transformative for experiments in the research area of open quantum systems. These experiments will deliver impact in two ways: by exploring new science and by laying the foundation for new technologies.New science: Molecular heat engines form an ideal platform for exploring the dialogue between quantum mechanics and thermodynamics. While some theoretical efforts have been undertaken towards this end, many predictions remain to be verified by experiments. New insights into thermodynamics on the molecular scale will also raise further questions: Does quantum coherence boost the thermoelectric efficiency of single-molecule heat engines? What happens if the Born-Oppenheimer approximation breaks down? Can molecular vibrational modes be electrically cooled to their ground state?New technologies: Thermoelectrics have a long history of providing simple, reliable power generation. Yet, the use of thermoelectric materials to recover waste heat has remained limited due to their scarcity and toxicity, and the unfortunate fact that the properties that determine their efficiency - the electrical conductance, the thermal conductance, and the Seebeck coefficient - are contra-indicated, meaning that an improvement to one will deteriorate another. Quantum effects in single-molecule heat engines lift the link between these contra-indicated properties, thereby opening up the possibility for highly efficient thermoelectric generators that could provide a low-cost, environmentally-friendly means of scavenging waste heat that would drastically decrease global energy consumption.This proposal seeks to develop the instrumentation and experimental methodology to investigate controlled thermoelectric heat-to-energy conversion in a single molecule, where the emphasis is on controlling the molecular interactions. This control will be achieved by using two-dimensional networks of nanoparticles linked via molecular junctions. Building on recent ground-breaking experiments, I will use electric-field control to tune the molecular energy level alignment with respect of the Fermi level of the substrate, while simultaneously controlling the tunnel coupling and applied bias voltage. A local heater will drive a thermally generated flow of electrons through a single molecule, which I will be able to optimize thanks to the unprecedented degree of tunability in the system. By probing the thermoelectric efficiency over a wide parameter space, I will establish the intrinsic thermodynamic limits to single-molecule energy conversion.