Adsorption on Individual Carbon Nanotubes

****技术摘要****本项目将进行实验，研究低维物质行为的基本方面，如一维或二维相变的动力学。它还将系统地研究吸附在碳表面上的原子与该表面上的电子之间的相互作用，这与石墨碳在气体和电荷的传感、过滤和储存方面的应用具有广泛的相关性。所使用的技术是将原子和分子层吸附在单个的单壁碳纳米管上，这些碳纳米管悬浮在一起，就像微型吉他弦一样。质量载荷引起的振动频率变化使原子密度接近原子精度，同时对纳米管电流的影响揭示了原子对电子的影响，其精度优于单电子精度。这种方法将在适当的时候扩展到更低的温度，在那里奇异的量子流体和固体行为可能局限于纳米管表面的圆柱形几何结构，也适用于石墨烯和其他衬底。该项目将支持两名博士生和几名本科生在纳米物理和纳米技术的广泛技术和原理方面的教育。****非技术摘要****碳材料在过滤、气体储存和锂离子电池等许多技术中发挥着至关重要的作用，这些技术依赖于碳表面与原子和分子的相互作用。这些相互作用是复杂的，而且令人惊讶地难以理解。这个项目将在纳米尺度上进行实验，这将比以前更精确、更有条理地确定和理解相互作用。这项技术包括将碳纳米管“纳米吉他晶体管”和后来的石墨烯“纳米鼓”暴露在精心控制的温度和压力下的气体中。通过测量纳米吉他或纳米鼓的音高变化，可以精确地测量粘在表面的原子数量，同时，通过测量电阻的变化，可以非常精确地确定与电子的相互作用。另一方面，同样的技术将在非常低的温度下用于研究超流动性和物质被限制在细长圆柱体表面的量子约束的基本物理。该项目将由两名博士生和几名本科生进行，他们将熟悉纳米物理和纳米技术的广泛技术和原理。

****Technical Abstract****This project will pursue experiments to investigate fundamental aspects of the behavior of matter in low dimensions, such as the dynamics of phase transitions in one or two dimensions. It will also investigate methodically the interactions between atoms adsorbed on a carbon surface and electrons in that surface, which is of wide-reaching relevance to uses of graphitic carbon in sensing, filtration, and storage of gases and of electrical charge. The technique used is to adsorb atomic and molecular layers on individual single-walled carbon nanotubes suspended like miniature guitar strings. The change in vibrational frequency due to mass loading yields the density of atoms to near atomic precision while the effect on the current along the nanotube simultaneously reveals the effect of the atoms on the electrons with better than single-electron precision. The approach will in due course be extended to lower temperatures where exotic quantum fluid and solid behavior may occur confined to the cylindrical geometry of the nanotube surface, and also to graphene and other substrates. The project will support the education of two PhD students and several undergraduates in the wide range of techniques and principles of nanoscale physics and nanotechnology.****Non-Technical Abstract****Carbon materials play crucial roles in many technologies, such as filtering, gas storage, and lithium ion batteries, which rely on the interactions of the surface of the carbon with atoms and molecules. Those interactions are complex and surprisingly poorly understood. This project will pursue experiments on the nanoscale that will allow far more precise and methodical determination and understanding of the interactions than has been possible before. The technique involves exposing carbon-nanotube "nanoguitar transistors" and later graphene "nanodrums" to gases at carefully controlled temperature and pressure. By measuring the change in pitch of the nanoguitar or drum, the number of atoms stuck to the surface can be accurately measured, while at the same time by measuring changes in the electrical resistance the interaction with the electrons can be determined with extraordinary precision. On the other hand, the same techniques will be employed at very low temperatures to investigate the fundamental physics of superfluidity and quantum confinement of matter restricted to the surface of a long thin cylinder. The project will be carried out by two PhD students and several undergraduates who will be familiarized with the wide range of techniques and principles of nanoscale physics and nanotechnology.