Manipulation of Hole-pinned Vortices: Classical and Quantum

孔钉涡的操纵：经典和量子

• 批准号: 1905742
• 负责人: John Ketterson
• 金额: $ 51万
• 依托单位: Northwestern University
• 依托单位国家: 美国
• 项目类别: Continuing Grant
• 财政年份: 2019
• 资助国家: 美国
• 起止时间: 2019-12-15 至 2023-11-30
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=1905742&HistoricalAwards=false
• 关键词: Manipulation; Hole; pinned; Vortices; Classical

Non-Technical AbstractSuperconductors, which transport electric current without loss, also expel a magnetic field. However, above some critical field magnetic flux enters a superconductor through the formation of an array of swirling currents of superconducting electrons, called vortices. The movement of these vortices can destroy the superconducting property. High field magnets avoid this problem due to microscopic defects that pin the vortices. Rather than having the vortices pinned randomly by defects, the approach of this research team is to pin them in a controlled way by creating patterns of nanoscopic holes within a thin film to which they attach. By introducing external electric and magnetic fields it should then be possible to move the vortices between the pinning sites in a controlled way. Such manipulations can, potentially, be used to either store data, perform calculations, or both, all within the same assembly of holes. Since vortices are inherently stable, being destroyed only at the edges of the film or on encountering an anti-vortex, the “information bits” they carry are secure. Furthermore, they can have sub micron dimensions and may respond on sub nanosecond time scales potentially facilitating high-speed, high density data processing. But vortices are also quantum mechanical in nature and this suggests the possibility they may be manipulated in a quantum mechanically coherent way by exploiting both quantum tunneling and superposition. Therefore, this project could lead to the development of devices for quantum information technology. The proposed project is in line with national goals to better understand and better exploit quantum phenomena. In addition, it will equip students with the expertise needed to join the work force of future industrial efforts to realize and exploit the principles and techniques established for quantum information technology.Technical abstractThis project aims to explore various quasi-static and dynamic properties of thin film vortices pinned on patterned holes in thin superconducting films. An external magnetic field perpendicular to the film will control the average flux density within the film, with special emphasis on strengths corresponding to an integer occupations. One class of experiments involves a search for resonant responses of vortices pinned on isolated holes, since displacement of the vortex center generates a restoring force. This project will in addition study the use of applied d.c. (or pulsed) currents, and in combination with oscillatory fields, to move vortices between neighboring pairs of holes, down a one-dimensional line of holes, or across a two dimensional array of holes, which should result in r.f./microwave emissions, the frequency of which is controlled by the hole spacing and the local current density. Application of an oscillatory current at the hopping frequency should produce Shapiro-like steps in the d.c transport characteristics. In the presence of quantum-tunneling between the neighboring potential wells, a single vortex pinned on the pair could distribute itself between the wells in a symmetric or antisymmetric manner from which two-state super-positions might be formed, which could be searched for spectroscopically. The manipulation of such vortices can be used as flux-flow oscillators, computer bits, or data storage elements. The phenomena to be examined, if realized, could, potentially, lead to new classes of super-conducting devices, all based on the manipulation of hole-pinned vortices. These include: i) various flux flow oscillators, a multi-bit flux line memory element, and iii) a possible qubit. Graduates of this program will be equipped to enter various industrial environments.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.

超导体可以无损耗地传输电流，同时也会产生磁场。然而，在某个临界场之上，磁通量通过形成超导电子的涡旋电流阵列（称为涡旋）进入超导体。这些涡旋的运动会破坏超导特性。高磁场磁铁避免了这个问题，由于微观缺陷，钉的漩涡。这个研究小组的方法不是让涡流随机地被缺陷固定，而是通过在它们附着的薄膜内创建纳米级孔的图案来以受控的方式固定它们。通过引入外部电场和磁场，应该可以以受控的方式在钉扎位置之间移动涡旋。这样的操作可以潜在地用于存储数据、执行计算或两者，所有这些都在相同的孔组件内。由于涡旋本身是稳定的，只有在胶片边缘或遇到反涡旋时才会被破坏，因此它们携带的“信息位”是安全的。此外，它们可以具有亚微米尺寸，并且可以在亚纳秒时间尺度上响应，从而潜在地促进高速、高密度数据处理。 但是涡旋在本质上也是量子力学的，这表明它们可能通过利用量子隧穿和叠加以量子力学相干的方式被操纵。因此，该项目可能会导致量子信息技术设备的开发。拟议的项目符合更好地理解和更好地利用量子现象的国家目标。此外，它将使学生具备所需的专业知识，加入未来的工业努力的劳动力，实现和利用的原则和技术建立的量子信息technology.Technical abstractionThis项目的目的是探索各种准静态和动态特性的薄膜涡旋钉扎在图案化的孔在薄超导薄膜。垂直于薄膜的外部磁场将控制薄膜内的平均通量密度，特别强调与整数占用相对应的强度。一类实验涉及到孤立的孔钉扎涡的共振响应的搜索，因为涡中心的位移产生的恢复力。本项目还将研究应用直流（或脉冲）电流的使用，并与振荡场相结合，以移动相邻孔对之间的涡流，沿着一维孔线，或穿过二维孔阵列，这将导致r.f./微波发射，其频率由孔间距和局部电流密度控制。在跳跃频率的振荡电流的应用程序应产生Shapiro样的步骤中的直流传输特性。在相邻的势威尔斯阱之间存在量子隧穿时，钉扎在势阱对上的单个涡旋可以以对称或反对称的方式在威尔斯阱之间分布，由此可能形成两态叠加，这可以通过光谱来搜索。这种涡旋的操纵可以用作通量流振荡器、计算机位或数据存储元件。待研究的现象，如果实现的话，可能会导致新的超导设备类别，所有这些都基于对孔钉扎涡旋的操纵。这些包括：i）各种通量流振荡器，多位通量线存储器元件，以及iii）可能的量子位。该奖项反映了NSF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

Investigation of the Critical Currents in Thin-Film MoGe Devices

薄膜 MoGe 器件中临界电流的研究

• DOI: 10.1109/tasc.2023.3343324
• 发表时间: 2024
• 期刊: IEEE Transactions on Applied Superconductivity
• 影响因子: 1.8
• 作者: Nevirkovets, Ivan P.;Grudichak, Scott T.;Belogolovskii, Mikhail;Ketterson, John B.
• 通讯作者: Ketterson, John B.

Temperature-dependent effect of modulation in graphene-supported metamaterials

• DOI: 10.1088/1367-2630/ac5dfa
• 发表时间: 2022-04-01
• 期刊: NEW JOURNAL OF PHYSICS
• 影响因子: 3.3
• 作者: Morozov，Yevhenii M.;Lapchuk，Anatoliy S.;Nevirkovets，Ivan P.
• 通讯作者: Nevirkovets，Ivan P.

Josephson Junctions with Artificial Superparamagnetic Barrier: A Promising Avenue for Nanoscale Magnetometry

具有人工超顺磁势垒的约瑟夫森结：纳米级磁力测量的有前途的途径

• DOI: 10.1103/physrevapplied.14.014092
• 发表时间: 2020
• 期刊: Physical Review Applied
• 影响因子: 4.6
• 作者: Nevirkovets, Ivan P.;Belogolovskii, Mikhail A.;Ketterson, John B.
• 通讯作者: Ketterson, John B.

Driven responses of periodically patterned superconducting films

周期性图案超导薄膜的驱动响应

• 发表时间: 2024
• 期刊: Physical Review B: Solid state
• 作者: Al Luhaibi, A.;Glatz, A;Ketterson, J. B.
• 通讯作者: Ketterson, J. B.

Magnetic Field Sensor Based on a Single Josephson Junction With a Multilayer Ferromagnet/Normal Metal Barrier

基于具有多层铁磁体/普通金属屏障的单约瑟夫森结的磁场传感器

• DOI: 10.1109/tasc.2021.3056039
• 发表时间: 2021
• 期刊: IEEE Transactions on Applied Superconductivity
• 影响因子: 1.8
• 作者: Nevirkovets, Ivan P.;Belogolovskii, Mikhail A.;Mukhanov, Oleg A.;Ketterson, John B.
• 通讯作者: Ketterson, John B.