Correlating Local Defect Structure with Dynamical Response in Graphene

该奖项的研究目标是将石墨烯纳米谐振器的局部原子级结构与其在高驱动频率下的非局部振荡响应相关联。这将通过将高分辨率扫描隧道显微镜与高频光电致动技术相结合来探测悬浮的石墨烯膜来进行。我们将调查夹紧，悬浮膜直径下降到25纳米，迄今为止，一直无法访问的动态测量制度。使用离子辐照，高能电子和吸附物沉积的组合，我们将控制和表征石墨烯纳米谐振器的特定缺陷和吸附物配置，并监测这如何影响它们的谐振和耗散行为。在这里，将使用扫描隧道显微镜的非线性隧道电流在一个新的整流模式，将作为高频表面振荡振幅和空间本征模式的灵敏探针。这将为测试多尺度理论模型提供一个强有力的新工具，该模型将联合收割机原子定义的缺陷配置与连续材料特性相结合。这项研究将探索已预测但从未观察到的新物理现象，例如特定缺陷配置对应变，悬浮石墨烯纳米谐振器的动态磁化率的影响。这项研究将实现一种全新的显微镜技术，将原子尺度的空间分辨率与高频动力学特性结合起来。这将有助于探索纳米结构过程和行为，这些过程和行为以前由于缺乏同时测量单个夹持石墨烯纳米谐振器的原子尺度特性和振荡响应的工具而无法获得。 对技术的潜在影响是强大的，因为这项工作应该导致新型的纳米谐振器，将适用于纳米电子学，通信，化学检测，质量传感，电荷传感，探测量子波动，以及在原子尺度上弹性行为的一般探索。对教育和外联的影响也将很大。本计画将在一个跨学科的领域提供研究生、大学生和高中生科学训练

The research objective of this award is to correlate the local, atomic-scale structure of graphene nanoresonators with their non-local oscillatory response at high driving frequencies. This will be performed by combining high-resolution scanning tunneling microscopy with high frequency opto-electric actuation techniques to probe suspended graphene membranes. We will investigate clamped, suspended membranes having diameters down to 25 nm, a regime that has so far been inaccessible to dynamical measurement. Using a combination of ion irradiation, high energy electrons, and adsorbate deposition, we will control and characterize specific defect and adsorbate configurations of graphene nanoresonators and monitor how this affects their resonant and dissipative behavior. The nonlinear tunnel current of a scanning tunneling microscope will be used here in a new rectifying mode that will serve as a sensitive probe of high frequency surface oscillatory amplitude and spatial eigenmodes. This will provide a powerful new tool for testing multi-scale theoretical models that combine atomistically defined defect configurations with continuum material properties.This research will explore new physical phenomena that have been predicted but never before observed, such as the effect of specific defect configurations on the dynamical susceptibility of strained, suspended graphene nanoresonators. The research will enable an entirely new technique of microscopy that marries atomic-scale spatial resolution with high-frequency dynamical characterization. This will facilitate the exploration of nanostructure processes and behavior that were previously inaccessible due to a lack of tools for simultaneously measuring the atomic scale properties and oscillatory response of individual clamped graphene nanoresonators. The potential impact on technology is strong, since this work should result in new types of nanoresonators that will be applicable in the areas of nano-electronics, communications, chemical detection, mass sensing, charge sensing, probing quantum fluctuations, and general exploration of elastic behavior at the atomic scale. The impact on education and outreach will also be strong. This project will provide scientific training to graduate students, undergraduates, and high school students in a strongly interdisciplinary area