GOALI: Advanced Cantilevers for MRFM with IBM Almaden

Sidles提出了一种重要的新成像技术，其中来自核磁共振（NMR）测量的力将被精确测量，足以允许单个原子的三维成像。电子纳米器件评估、基因测序、药物开发、存储介质分析以及许多其他医药、医疗和工业应用将受益于这种新的成像技术。 磁共振力显微镜（MRFM）的基本挑战在于必须检测到的非常小的力，其数量级为阿托牛顿（1 aN=10- 18 N）。 热机械噪声作为力的波动，是制约机械杠杆力检测灵敏度的根本因素。 为了实现MRFM所需的非常高的灵敏度，悬臂梁的温度和刚度必须最小化，同时最大化Q。 通过MRFM获得单原子成像的研究已经在Rugar的IBM Almaden小组进行了几年，并且已经取得了重大进展。 最近的研究已经包括检测阿托-牛顿力的能力的演示，许多fN-sale部队附近的表面的观察，并努力确定和减少热机械噪声的机制在用于检测这些力量的杠杆。 所有这些都是在斯坦福大学和IBM之间的GOALI资助的合作中发生的，该合作的特点是在IBM进行学生研究，并使用斯坦福大学的NNUN设施制造独特的杠杆。 我们的目标在这个更新的努力集中在cnued工作，以了解和减少阻尼机制的微机械杠杆，限制Q值。 我们已经构建了一个设备，允许系统的实验测量悬臂梁Q作为温度，尺寸和材料的函数，我们将使用它来识别阻尼机制。 此外，我们建议开发一种新的微机械悬臂梁的设计，将允许原位退火的MRFM设备。 此外，我们还利用这些敏感的悬臂梁开发了一种新的表面耗散显微镜，其中悬臂梁上的陷阱电荷诱导表面电荷，其迁移率可以在纳米尺度上确定。 我们将继续沿着这三个方向开展工作。 长期目标仍然是单原子MRFM成像的演示。

An important new imaging technique has been proposed by Sidles, in which forces derived from a Nuclear Magnetic Resonance (NMR) measurement would be measured accurately enough to allow 3-dimensional imaging of individual atoms. Electronic nanodevice evaluation, gene sequenceing, drug development, ananlysis of storage media, and many other commerical, medical and industrial applicatons would would benefit from this new imaging technology. The basic challenge of Magnetic Resonance Force Microscopy (MRFM) lies in the exceedingly small forces which must be detected, which are of order atto-newtons (1 aN=10-18N). Force detection sensitivity of mechanical cantilevers is ultimately limited by thermo-mechanical noise which apprears as a force fluctuation. To achieve the very high sensitivity required for MRFM, the temperature and stiffness of the cantilever must be minimized while maximizing Q. Research to obtain sngle-atom imaging by MRFM has been underway in Rugar's IBM Almaden group for several years, and significant progress has occurred. Recent research has included demonstrations of the ability to detect atto-newton forces, observation of numerous fN-sale forces near surfaces, and work to identify and reduce the mechanism for thermo-mechanical noise inthe cantilevers used to detect these forces. all of this has taken place during a GOALI-Funded collaboration between Standford and IBM, which has featured student research at IBM and use of NNUN facilities at Stanford to fabricate unique cantilevers. Our goals in this renewal effort focus on cntinued work to understand and reduce the damping mechanism in micromechanical cantilevers that limit the value of Q. We have constructed an apparatus which allows systematic experimental measurements of cantilever Q as a function of temperature, dimensions, and materials, and we will use this to identify damping mechanisms. Also we propose to develop a new design for a micromechanical cantilever that will allow in-situ annealing in the MRFM apparatus. In addition, we have used these sentisitve cantilevers to develop develop a novel surface dissipation microscopy, in which trapped charges on the cantilever induce surface charges whose mobility can be determined on the nm-scale. Work along all 3 of these directions will continue. The long-term goal remains the demonstration of MRFM imaging of sigle atoms.