CAREER: Skyrmion-Vortex Interactions in Ferromagnet-Superconductor Heterostructures

非技术摘要：自旋电子学领域是一个快速发展和颠覆性的研究领域，产生了优于传统计算电子学的新设备方案。传统的电子元件使用电子电荷来存储和传输信息。例如，电容器上累积的电荷量可以决定它是贡献一个“0”还是一个“1”二进制数。另一方面，自旋电子设备利用电子的另一种特性，称为自旋(向上、向下或倾斜)来编码信息。与传统的基于半导体晶体管的逻辑相比，这些器件实际上可以使用自旋电流来更快、更高效地控制逻辑操作。自旋电子器件通常由铁磁体组成，作为自旋电流的来源。加入没有电阻的超导体元素，可以提高器件的整体性能，并提供新的功能，例如非常低的损耗(能量损失)自旋传输。这种铁磁超导体结构也是拓扑量子计算方案的组成部分，拓扑量子计算是一种预计对困扰其他量子设备平台的环境噪声具有健壮性的架构。该项目研究铁磁超导器件，通过对整个器件中的纳米级磁场成像，并确定温度和外加电流对器件运行的影响，从而形成新型计算架构的构建块。这项努力还通过设计一门新颖的实验室课程，教授量子传感和计算职业的基础技能，并为当地一所小学的K-12学生提供电子学培训，为美国具有全球竞争力的量子劳动力的发展做出了贡献。技术摘要：铁磁-超导体(FS)异质结是超导自旋电子学和拓扑量子计算的重要平台。在FS异质结中，理论上预测可以形成适合于计算应用的天子涡对。这个项目的目标是设计、制造和研究一个天空粒子和涡旋共存并相互作用的系统。具体地说，研究小组研究了两种不同FS异质结构中的邻近耦合：碲化锗铁(FGT)-超导体双层和超导层下的FeGe岛阵列。对于这两种异质结构，他们使用磁力显微镜和电输运测量来研究在不同温度(低至1.6K)和磁场(高达12T)下出现在这些器件中的磁性织构的动力学，确定天离子和涡旋共存和束缚的条件。拟议的工作包括研究热能和电流诱导力的影响，并将结果与描述天空-涡旋对动力学的半经典理论进行比较。这一奖项反映了NSF的法定使命，并通过使用基金会的智力优势和更广泛的影响审查标准进行评估，被认为值得支持。

Non-technical abstract:The field of spintronics is a rapidly advancing and disruptive research area, producing novel device schemes that are superior to conventional computing electronics. Conventional electronic elements use electron charge to store and transmit information. For example, the amount of charge accumulated on a capacitor may determine whether it contributes a “0” or a “1” binary digit. On the other hand, spintronic devices exploit another property of electrons, called spin (up, down, or canted), to encode information. These devices can in fact use spin currents to control logic operations faster and more energy efficiently than charge currents can accomplish in conventional semiconductor transistor-based logic. Spintronics devices typically consist of ferromagnets as the source of the spin current. Incorporating elements that are superconductors, which have no electrical resistance, can enhance the overall device performance and offer new functionalities, such as remarkably low-dissipation (energy loss) spin transport. Such ferromagnetic-superconductor structures are also constituents of schemes for topological quantum computing, an architecture that is predicted to be robust to environmental noise that plagues other quantum device platforms. This project investigates ferromagnetic-superconductor devices that could form building blocks of novel computing architectures by imaging nanoscale magnetic fields throughout the device and determining the effects of temperature and an applied current on the device operation. This effort also contributes to the development of a globally competitive quantum workforce in the U.S. by designing a novel lab course that teaches foundational skills for careers in quantum sensing and computing, and providing training in electronics to K-12 students at a local elementary school. Technical abstract:Ferromagnet-superconductor (FS) heterostructures are promising platforms for superconducting spintronics and topological quantum computing. In FS heterostructures, it is theoretically predicted that skyrmion-vortex pairs can form that are desirable for computing applications. The objective of this program is to design, fabricate, and study a system in which skyrmions and vortices co-exist and interact. Specifically, the research team studies proximity coupling in two different FS heterostructures: iron germanium telluride (FGT) - superconductor bilayers and arrays of FeGe islands under a superconducting layer. For both heterostructures, they employ magnetic force microscopy and electrical transport measurements to study the dynamics of magnetic textures that emerge in these devices under variable temperatures (down to 1.6 K) and magnetic fields (up to 12 T), determining the conditions under which skyrmions and vortices co-exist and bind. Proposed work includes studies of the effects of thermal energy and current-induced forces, and comparing the results to semiclassical theories describing skyrmion-vortex pair dynamics.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.