Confined carbyne for optoelectronics and optomechanics

本项目将碳炔（碳纳米管内部碳原子的一维线性链）作为一种新的材料系统，通过光机械相互作用操纵分子振动，并实现原子尺度上的晶体管。我将利用碳炔的两个独特性质，这两个性质直接来自碳炔的原子结构。卡宾是一种Peierls材料，其存在于金属相中，其中原子通过双键连接，并且存在于具有交替的单键和三键的半导体相中。碳炔可以通过掺杂在两相之间切换，这将允许我使用碳炔作为晶体管沟道，其中电流通过改变碳炔的结构相来控制。这使得纳米级晶体管能够在绝对较低的尺寸限制下具有一个原子的沟道横截面，并且与通过掺杂半导体来控制电流的传统晶体管架构完全不同。最近的理论工作建议通过分子与等离子体纳米结构的强光场的光机械相互作用来操纵分子振动（声子）。这将宏观谐振器和光学腔之间的光机械相互作用的概念转移到分子尺度，并预测了百万倍更强的光机械耦合率。声子可以作为信息载体，并允许在光力学中研究量子力学效应。然而，目前的实验实现失败，由于分子衰变所产生的等离子体激元结构的强光场驱动。在这里，我建议通过利用碳炔的异常高的拉曼散射截面来克服这个限制，分子振动被光非弹性散射的速率。这降低了进入光机械相互作用机制所需的场强，并将使我能够在碳炔中制备非热声子种群。声子激光和相关光子的发射是分子光机械相互作用的两个有趣的结果将被证明。该项目最初旨在探索受限碳炔的声子和激发动力学以及这些性质如何受到宿主纳米管的影响。我将通过结合尖端增强、温度和波长相关的拉曼光谱来实现这一点。受限碳炔将被带入设备配置中，并通过介电泳沉积与等离子体结构接合，其中纳米管充当载体系统。电输运测量将验证碳炔晶体管的功能。该项目将受限碳炔作为一种新的材料系统来研究分子光学力学，并将使我能够探索新的现象，如分子尺度上的光的频率转换。

This project will establish carbyne, a one-dimensional linear chain of carbon atoms inside a carbon nanotube, as a new material system to manipulate the molecular vibrations through optomechanical interaction, and to realize a transistor on the atomic scale. I will exploit two unique properties of carbyne that arise directly from its atomic structure. Carbyne is a Peierls material which exists in a metallic phase where the atoms are connected by double bonds, and in a semiconducting phase with alternating single and triple bonds. Carbyne can be switched between the two phases by doping, which will allow me to use carbyne as a transistor channel where the current flow is controlled by changing the structural phase of carbyne. This enables a nanoscale transistor at the absolute lower size limit with a channel cross section of one atom, and differs radically from conventional transistor architectures where the current flow is controlled by doping a semiconductor. Recent theoretical works suggest to manipulate molecular vibrations (phonons) through the optomechanical interaction of a molecule with the intense light fields of a plasmonic nanostructure. This transfers the concept of optomechanical interaction between a macroscopic resonator and an optical cavity to the molecular scale, and predicts million-fold stronger optomechanical coupling rates. Phonons can then act as information carriers and allow for the study of quantum-mechanical effects in optomechanics. Current experimental realizations, however, fail due to molecular disintegration driven by the strong light fields generated by the plasmonic structures. Here, I suggest to overcome this limitation by exploiting the exceptionally high Raman scattering cross section of carbyne, the rate at which molecular vibrations are scattering inelastically by light. This reduces the field intensities required to enter the regime of optomechanical interaction and will allow me to prepare non-thermal phonon populations in carbyne. Phonon lasing and the emission of correlated photons as two of the intriguing consequences of molecular optomechanical interaction will be demonstrated.The project initially aims at exploring the phonon and excitation dynamics of confined carbyne and how these properties are influenced by the host nanotubes. I will achieve this by combining tip-enhanced, temperature-, and wavelength dependent Raman spectroscopy. Confined carbyne will be brought into a device configuration and interfaced with plasmonic structures by dielectrophoretic deposition, where the nanotube acts as a carrier system. Electrical transport measurements will verify the functionality of the carbyne transistor. The proposed project establishes confined carbyne as a new material system to study molecular optomechanics and will allow me to explore new phenomena such as the frequency conversion of light on the molecular scale.