Coherent Thermal and Electrical Transport in Mesoscopic Structures

** 非技术性摘要 ** 电子电路的日益小型化，使得更快的计算机和更薄的手机得以发展，目前正面临两个问题：使今天的技术变得更小的障碍是什么？能否制造出基于量子效应的新型设备？ 这个个人研究者奖支持一个项目，将解决这两个问题。 缩小当前设备的最大障碍之一是，随着计算机芯片变得越来越小，它们会变得越来越热。 在解决这个问题时，拟议的研究将试图了解纳米级导线热传导背后的基本物理学，这似乎与较大导线的热传导不同。 这项研究将通过研究不同材料之间的相互作用来推动新型设备的发展，这些材料之间的量子相互作用足够小，可以产生新的物理效应，用于未来的技术。 除了培训研究生和博士后，该项目还将培训本科生和高中生在微观和纳米尺度上制作物体的基本技术。技术摘要 ** 该个人研究奖支持一个项目，该项目探索由超导（S）、正常金属（N）和铁磁（F）材料组成的金属介观异质结构的电学和热学性质。 电输运实验将研究由材料之间的邻近效应引起的一系列广泛的相干过程。 这些实验将包括FSF器件中的三重态超导性，NSN和FSF器件中的非局部Andreev反射以及SNS器件中的可调π结的研究。 热输运实验将追踪纳米结构中异常行为的先前观察结果，包括正常金属线中可能偏离Wiedemann-Franz定律的情况以及Andreev干涉仪热功率中无法解释的对称性。 虽然这些设备的最关键的制造步骤和毫开尔文温度测量将由研究生和博士后进行，但一些纳米和微制造步骤将由本科生和当地高中生进行，培训他们电子束和光刻的基础知识。

*****NON-TECHNICAL ABSTRACT******The increasing miniaturization of electronic circuitry that allows the development of faster computers and slimmer cell phones is presently facing two questions: what impediments are there to making today's technology even smaller? and can fundamentally new types of devices, based on quantum effects, be manufactured? This individual investigator award supports a project that will address both of these questions. One of the biggest obstacles to shrinking current devices is that as computer chips get smaller and smaller they heat up more and more. In addressing this problem the proposed research will attempt to understand the basic physics behind heat conduction for wires that are on the nanometer scale, which appears to differ from heat conduction in larger wires. This research will advance the drive towards fundamentally new types of devices by looking at the interplay between different materials on size scales small enough that the quantum interactions between these materials yield new physical effects that could be harnessed for future technologies. In addition to training graduate students and post-docs, this project will train undergraduates and high school students in basic techniques for making objects on the micro- and nanoscales.*****TECHNICAL ABSTRACT******This individual investigator award supports a project exploring the electrical and thermal properties of metallic, mesoscopic heterostructures composed of superconducting (S), normal-metal (N), and ferromagnetic (F) materials. The electrical transport experiments will examine a broad array of coherent processes caused by proximity effects between the materials. These experiments will include investigations into triplet superconductivity in FSF devices, non-local Andreev reflection in NSN and FSF devices, and tunable pi-junctions in SNS devices. The thermal transport experiments will pursue prior observations of anomalous behavior in nanoscale structures, including possible deviations from the Wiedemann-Franz law in normal-metal wires and unexplained symmetries in the thermopower of Andreev interferometers. While the most critical fabrication steps and milliKelvin temperature measurements of these devices will be undertaken by graduate students and post-docs, some nano- and microfabrication steps will be performed by undergraduate and local high school students, training them in the basics of e-beam and photolithography.