Collaborative Research: Kinetic Inductance in Superconducting Nanowire Microwave Devices

合作研究：超导纳米线微波器件中的动感电感

• 批准号: 2000743
• 负责人: Karl Berggren
• 金额: $ 38.3万
• 依托单位: Massachusetts Institute of Technology
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 2020
• 资助国家: 美国
• 起止时间: 2020-04-01 至 2024-03-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=2000743&HistoricalAwards=false
• 关键词: Collaborative; Research; Kinetic; Inductance; Superconducting

Proposal Title:Collaborative Research: Kinetic Inductance in Superconducting Nanowire Microwave DevicesNon-Technical AbstractSuperconducting nanowires can have a kinetic inductance that is several orders of magnitude larger than their magnetic inductance. As a result, high frequency signals on the nanowire experience significant spatial compression as well as a significant reduction in their velocity. The kinetic inductance also varies nonlinearly as a function of the current, creating an opportunity for realizing nonlinear phenomena with extremely minimal dissipation. Through a combination of theory, modeling, and experiment, this project will study these effects in different superconducting nanowire materials and geometries. The understanding gained from these studies will be applied to design new types of ultra-compact microwave devices, which will then be fabricated and characterized. Such devices can serve as important building blocks for the development of more complex systems based on superconducting circuits such as single-photon imagers and quantum computers. This collaborative project brings together groups at Massachusetts Institute of Technology and the University of North Florida, an undergraduate-education focused university, to conduct the proposed research and educational activities, combining the best aspects of both institutions. In particular, the involvement of the University of North Florida creates additional opportunities for undergraduates from diverse backgrounds to participate in the research.Technical AbstractThe goal of this project is to create a new superconducting nanowire device platform that can serve as the basis of a monolithic superconducting nanowire microwave integrated circuit technology. This goal will be pursued through four approaches. The first approach is based on exploring materials and geometries that maximize the nanowire's kinetic inductivity, which will result in extremely large characteristic impedances ( 10 kohm) along with slow signal velocities and large spatial compression of the signal wavelengths. Such high impedances create strong decoupling from the environment and have potential applications ranging from the readout of superconducting nanowire single-photon detectors to the design of quantum bits. The second approach will be to fabricate nanowires on extremely high permittivity substrates such as strontium titanate, which has been shown to have a relative permittivity as high as 10,000 at low temperature. This extremely large permittivity will significantly boost the capacitance, bringing the characteristic impedance of high-inductance nanowires close to 50 kohm while simultaneously achieving ultra-slow signal velocities and ultra-compressed signal wavelengths. A 50 kohm impedance is critical to coupling with conventional microwave circuitry. The third approach will focus on understanding and exploiting the nonlinear current-dependence of kinetic inductance in order to create new types of nanowire-based nonlinear microwave devices. Examples of such devices include mixers, tunable couplers, switches, and parametric amplifiers. In order to understand these devices, the project will seek to address fundamental questions such as how quickly the nanowire's kinetic inductance can be modulated, how much loss is associated with this modulation, and how the nonlinearity and the loss depend on the signal power. The fourth approach will leverage the results generated in the first three approaches to develop more complex nanowire-based devices and circuits.This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.

提案题目：合作研究：超导纳米线微波器件的动态电感非技术摘要超导纳米线的动态电感可以比其磁感应大几个数量级。因此，纳米线上的高频信号经历了显著的空间压缩以及速度的显著降低。动态电感也作为电流的函数非线性变化，创造了以极小耗散实现非线性现象的机会。通过理论、模型和实验相结合的方法，本项目将研究不同超导纳米线材料和几何形状下的这些效应。从这些研究中获得的理解将应用于设计新型超紧凑微波器件，然后将制造和表征。这种设备可以作为开发基于超导电路的更复杂系统（如单光子成像仪和量子计算机）的重要基石。这个合作项目将麻省理工学院和北佛罗里达大学（一所注重本科教育的大学）的小组聚集在一起，结合两所机构的最佳方面，进行拟议的研究和教育活动。特别是，北佛罗里达大学的参与为来自不同背景的本科生参与研究创造了额外的机会。技术摘要：本课题的目标是建立一个新的超导纳米线器件平台，作为单片超导纳米线微波集成电路技术的基础。这一目标将通过四个途径实现。第一种方法是基于探索材料和几何形状来最大化纳米线的运动电感，这将导致极大的特征阻抗（10 khm），伴随着缓慢的信号速度和大的信号波长空间压缩。如此高的阻抗产生了与环境的强去耦，从超导纳米线单光子探测器的读出到量子比特的设计，都有潜在的应用。第二种方法是在极高介电常数的衬底上制造纳米线，如钛酸锶，其在低温下的相对介电常数高达10,000。这种极大的介电常数将显著提高电容，使高电感纳米线的特性阻抗接近50 kohm，同时实现超慢信号速度和超压缩信号波长。50欧姆的阻抗是与传统微波电路耦合的关键。第三种方法将侧重于理解和利用动态电感的非线性电流依赖性，以创建新型的基于纳米线的非线性微波器件。这类器件的例子包括混频器、可调谐耦合器、开关和参数放大器。为了了解这些器件，该项目将寻求解决一些基本问题，如纳米线的动态电感可以多快被调制，与这种调制相关的损耗有多大，以及非线性和损耗如何依赖于信号功率。第四种方法将利用前三种方法产生的结果来开发更复杂的基于纳米线的器件和电路。该奖项反映了美国国家科学基金会的法定使命，并通过使用基金会的知识价值和更广泛的影响审查标准进行评估，被认为值得支持。

项目成果

Compact and Tunable Forward Coupler Based on High-Impedance Superconducting Nanowires

• DOI: 10.1103/physrevapplied.15.024064
• 发表时间: 2020-11
• 期刊: arXiv: Applied Physics
• 作者: M. Colangelo;Di Zhu;D. Santavicca;B. Butters;J. Bienfang;K. Berggren