SGER: Tuning the Conductance of Nanoparticle Arrays

*非技术摘要*目前，人们的注意力主要集中在金属、磁性或半导体纳米粒子及其显著的光学和电学性质上。相比之下，超导纳米粒子及其组装成更大结构的情况在很大程度上还没有被探索过。这个探索性研究的小资助金调查了从精选的纳米尺寸超导体粒子中创造新一代固体的可能性。它汇集了粒子组装和纳米制造的创新想法。这项工作的重点将是探索调整自组装纳米颗粒阵列的电导的方法。从这项研究中获得的理解可能会导致开发用于磁性和电子应用的新材料。与此同时，该项目将使有能力的研究生沉浸在物理学和材料科学之间的跨学科纳米科学研究中。物质的超导、金属和绝缘态之间的转变的性质一直是凝聚态物理学中最耐人寻味的谜题之一。多年来，超薄超导薄膜一直是研究绝缘体向超导体转变的主力。然而，它们的局部形态往往很难确定和控制。为了研究这种转变的新方法，这项探索性研究的小赠款将胶体自组装和纳米制造的创新想法结合在一起，以生产高度有序的纳米颗粒阵列。在这样的阵列中，电导是通过包裹每个颗粒并设置颗粒间距的短有机分子的颗粒间隧道作用来确定的。这项工作的重点是探索调整隧道电导的方法。如果这种电导能够被驱动到量子电阻附近，那么应该不仅可以从绝缘态进入金属状态，而且对于超导纳米粒子来说，还可以进入全局超导状态。该项目将为有能力的研究生提供广泛的纳米制造技术以及电子传输测量方面的技能。

*****NON-TECHNICAL ABSTRACT***** Currently, much attention focuses on metallic, magnetic or semiconducting nanoparticles and their remarkable optical and electronic properties. By contrast, superconducting nanoparticles and their assembly into larger structures are largely unexplored. This Small Grant for Exploratory Research investigates the possibility to create a new generation of solids from carefully selected nanometer-size particles that are superconductors. It brings together innovative ideas from particle assembly and nanofabrication. The focus of this effort will be to explore means to tune the conductance of self-assembled nanoparticle arrays. The understanding gained from this research is likely to lead to the development of new materials for magnetic and electronic applications. At the same time, this project will immerse competent graduate students in interdisciplinary nanoscience research at the interface between physics and materials science. *****TECHNICAL ABSTRACT***** The nature of the transition between the superconducting, metallic and insulating states of matter has remained one of the most intriguing puzzles in condensed matter physics. Ultrathin superconducting films for many years have been a workhorse for investigations of the insulator to superconductor transition. However, their local morphology is often difficult to ascertain and control. For a new approach to investigate this transition, this Small Grant for Exploratory Research brings together innovative ideas from colloid self-assembly and nanofabrication to produce highly-ordered nanoparticle arrays. In such arrays the conductance is determined by inter-particle tunneling through short organic molecules that coat each particle and set the inter-particle spacing. The focus of this effort is to explore means to tune the tunneling conductance. If this conductance can be driven into the vicinity of the quantum resistance it should be possible to cross from the insulating state not just into a metallic but also, for superconducting nanoparticles, into the globally superconducting state. The project will provide competent graduate students with skills across a broad range of nanofabrication techniques as well as electronic transport measurements.