研究纳米超导量子干涉器件中的磁通噪声起源

项目名称： 研究纳米超导量子干涉器件中的磁通噪声起源

项目编号： No.61306151

项目类型： 青年科学基金项目

立项/批准年度： 2014

项目学科： 无线电电子学、电信技术

项目作者： 陈垒

作者单位： 中国科学院上海微系统与信息技术研究所

项目金额： 25万元

中文摘要： 纳米超导量子干涉器件(NanoSQUID)作为一种精密的自旋探测器,可以广泛应用于开发超高密度存储器和搜寻量子信息单元等诸多研究领域。目前，NanoSQUID的灵敏度主要受限于其磁通噪声，但对于引起磁通噪声的原因尚不完全清楚。本项目拟通过改变nanoSQUID的三个主要条件，研究其磁通噪声的可能起源和影响因素。条件一，考察超导金属和nanoSQUID衬底界面态上的局部磁偶极子对磁通噪声的影响。条件二，测量nanoSQUID衬底表面或内部缺陷产生的悬空键自旋涨落对磁通噪声的影响。条件三，分析磁通噪声和nanoSQUID的测量参数（测量电流频率、外加磁场以及环境温度）的关系。通过以上研究，系统地分析NanoSQUID磁通噪声的可能起源，可进一步理解磁通噪声的微观机理，为优化NanoSQUID的灵敏度提供科学指导依据。

中文关键词： 纳米超导量子干涉器件；磁通调制深度；磁通噪音；单电子自旋探测；微纳工艺

英文摘要： Nano-SQUID (superconducting quantum interference device) has drawn many attentions due to its possibility to achieve single-electron-spin detection by using of only electronic readout. Owning to its super sensitivity and easy accessibility, nano-SQUID is a highly desired technique for a variety of research areas requiring nanoscale magnetism characterization and quantum spin detection, such as studying super high density memory, searching for the quantum information storage unit-qubit, and developing nanoscale magnetic resonance imaging technique. The minimium detectable spin number of a nano-SQUID is proportional to the size of its superconducting ring and the magnetic flux noise. With the recent global trend to shrink the size of SQUID using nanotechnology, the sensitivity of current nano-SQUIDs is limited by the flux noise. However, the origins of the flux noise in superconducting device is still an unanswered question in condensed matter physics, and multiple hypotheses still remain at the stage of numerical simulation. Here, we propose to investigate the origins of the nano-SQUID flux noise experimentally by comparing nano-SQUID prepared using different methods. First, we will study the effect of local magnetic moments generated by the metal induced state at the interface between the niobium and the device

英文关键词： nanoSQUID；flux modulation depth；flux noise；single spin detection；nanotechnology