Mesoscopic Magnetic Measurements

*******技术摘要*******该个人研究者奖将支持使用基于稀释冰箱的扫描超导量子干涉装置（SQUID）对介观正常金属环进行直接磁测量。由于环周围的量子力学相相干性，正常金属环中应该存在持续电流，并且已经在理论上进行了广泛的研究。然而，只有一项研究测量了单个扩散环，可能是因为测量单个介观样品的小信号很困难。PI和她的学生提议用扫描SQUID来研究这些系统，这将能够在每次冷却期间测量许多介观样品的性质，一次一个样品，为介观理论的一些深刻的理论结果提供急需的实验输入。这些高要求的实验将为在一个智力丰富的研究环境中培养一些国家顶尖的年轻科学家提供直接的教育效益。本科生和研究生将学习纳米技术和精密测量技术以及基础物理。*******非技术摘要*******介观物理学是研究足够小的材料和器件，使量子力学效应发挥重要作用的学科。对单个样品的直接磁测量很重要，但很少，因为磁信号很弱。超导量子干涉装置（squid）可以说是世界上最灵敏的磁探测器。该奖项将支持使用不寻常的低温SQUID对金属量子力学理论中一些最引人注目的预测进行直接磁测量。在这项工作中采用的扫描方法将为介观理论的一些深刻的理论结果提供实验输入。除了其自身的智力价值，这项工作将通过维护一个非常不寻常的扫描SQUID显微镜来支持和加强国家的科学基础设施，该显微镜也与其他新材料的研究人员合作使用。这些高要求的实验将为在一个智力丰富的研究环境中培养一些国家顶尖的年轻科学家提供直接的教育效益。本科生和研究生将学习纳米技术和精密测量技术以及基础物理。

*******Technical Abstract*******This individual investigator award will support the use of a dilution-refrigerator-based scanning Superconducting QUantum Interference Device (SQUID) to make direct magnetic measurements of mesoscopic normal metal rings. Persistent currents in normal metal rings should exist as a result of quantum-mechanical phase coherence around the ring and have been extensively studied theoretically. However, only one study measured single diffusive rings, presumably because of the difficulty of measuring the small signal from a single mesoscopic sample. The PI and her students propose to study these systems with a scanning SQUID, which will enable measurement of the properties of many mesoscopic samples, one sample at a time, in each cooldown, providing much-needed experimental input on some of the profound theoretical results of mesoscopics theory. These highly demanding experiments will provide the direct educational benefit of training some of the nation's top young scientists in an intellectually rich research environment. Undergraduate and graduate research students will learn nanotechnology and precision measurement techniques as well as fundamental physics. *******Nontechnical abstract*******Mesoscopic physics is the study of materials and devices that are sufficiently small for quantum-mechanical effects to be important. Direct magnetic measurements on single samples are important, but rare, because the magnetic signal is weak. Superconducting QUantum Interference Devices (SQUIDs) are arguably the world's most sensitive magnetic detectors. This award will support the use of an unusual low-temperature SQUID to make direct magnetic measurements of some of the most striking predictions of the quantum-mechanical theory of metals. The scanning approach employed in this work will provide experimental input on some of the profound theoretical results of mesoscopics theory. Beyond its own intellectual merit, this work will support and enhance the nation's scientific infrastructure through the maintenance of a very unusual scanning SQUID microscope which is also used collaboratively with other investigators of novel materials. These highly demanding experiments will provide the direct educational benefit of training some of the nation's top young scientists in an intellectually rich research environment. Undergraduate and graduate research students will learn nanotechnology and precision measurement techniques as well as fundamental physics.