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颖设备方案。传统的电子元件利用电子电荷来存储和传输信息。例如，电容上累积的电荷量可以决定它是输出二进制数字“0”还是“1”。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。事实上，这些器件可以使用自旋电流来控制逻辑运算，比传统半导体晶体管逻辑中的电荷电流更快、更高效。自旋电子学设备通常由铁磁体组成，作为自旋电流的来源。将没有电阻的超导体元素结合在一起，可以提高设备的整体性能，并提供新的功能，例如非常低的耗散（能量损失）自旋输运。这种铁磁超导体结构也是拓扑量子计算方案的组成部分，这种架构预计对困扰其他量子设备平台的环境噪声具有鲁棒性。该项目研究了铁磁超导体器件，通过对整个器件的纳米级磁场进行成像，并确定温度和施加电流对器件运行的影响，这些器件可以形成新型计算体系结构的基石。通过设计一门新颖的实验课程，教授量子传感和计算职业的基本技能，并为当地小学的K-12学生提供电子方面的培训，这一努力也有助于美国发展具有全球竞争力的量子劳动力。技术文摘：铁磁-超导体异质结构是超导自旋电子学和拓扑量子计算的理想平台。在FS异质结构中，理论上预测可以形成计算应用所需的skyrron -vortex对。这个项目的目标是设计、制造和研究一个系统，在这个系统中，天空和漩涡共存并相互作用。具体来说，研究小组研究了两种不同FS异质结构中的接近耦合：碲化铁锗(FGT) -超导双层和超导层下的FeGe岛阵列。对于这两种异质结构，他们采用磁力显微镜和电输运测量来研究在可变温度（低至1.6 K）和磁场（高达12 T）下这些器件中出现的磁性结构的动力学，确定了skyrmions和涡旋共存和结合的条件。建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skyrmins -vortex对动力学的半经典理论进行比较。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。

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.