Spin Orbitronics: Interfacial Design of Spintronic Materials and Devices

近几十年来，计算和通信技术的显著进步是建立在传统电子技术的基础上的，而传统电子技术的基本极限正在迅速接近。为了满足未来对低功耗、高性能存储和逻辑器件的需求，迫切需要新的物理机制和先进的材料来利用它们。一种有希望的方法是在广为人知的自旋电子学范式中利用电子自旋自由度。实现自旋电子学技术的关键是在纳米器件中有效地操纵电子自旋的能力。这项研究计划寻求从根本上理解在磁性和非磁性材料之间的界面上出现的令人兴奋的新现象，这些现象为操纵电子自旋提供了强大的新机制。基础研究将产生广泛的技术影响，使新型自旋电子设备能够用于超低功率、高性能计算和海量数据存储，显著影响移动计算和全球能源效率。该计划将培训本科生和研究生先进的纳米技术，并通过国际合作提供丰富。通过将研究生与本科生、当地高中教师和代表性不足的学生合作，将研究、教育和外展高度结合起来。将利用MITX/EDX在线教育平台开发和广泛传播教育媒体，包括教学实验室单元和课程材料。这一研究计划将提供对超薄铁磁异质结构中产生的非常规电流感生扭矩和手性自旋织构的基本理解，这些超薄铁磁异质结具有破坏的反转对称性和强烈的自旋-轨道耦合。该计划的目标是(1)定量和系统地表征铁磁/重金属双层膜中的自旋轨道扭矩，以确定它们与界面材料和结构的关系；(2)从机理上理解存在强自旋轨道耦合时的磁化转变和磁畴壁运动；以及(3)建立优化自旋电子器件这些现象所需的材料设计原则。实验主要集中在过渡金属和合金上，这些过渡金属和合金的有序程度远远高于室温，与非磁性重金属和氧化物介电材料相互作用，这些材料易于与传统的半导体制造工艺集成。这些基础研究的学术价值包括对表面和界面磁性的重要新见解，纳米系统对称性破坏的量子力学效应，以及电荷和自旋自由度之间的耦合。基础研究将带来革命性的基于自旋的存储器和逻辑器件功能，以超低功耗要求提供增强的性能和耐用性。

The remarkable advances in computing and communications technologies in recent decades have been based on conventional electronics whose fundamental limits are rapidly being approached. In order to meet the demands for future low-power, high-performance memory and logic devices, new physical mechanisms and advanced materials that exploit them are urgently required. A promising approach is to harness the electron spin degree of freedom in a paradigm widely known as spintronics. The key to realizing spintronics technologies is the capability to efficiently manipulate the electron spin in nanoscale devices. This research program seeks a fundamental understanding of exciting new phenomena that emerge at interfaces between magnetic and nonmagnetic materials, which offer powerful new mechanisms to manipulate electron spins. The fundamental research will have broad technological impact by enabling new classes of spintronic devices for ultralow-power, high-performance computation and mass data storage, significantly impacting mobile computing and global energy efficiency. The program will train undergraduate and graduate students in advanced nanotechnologies, and provide enrichment through international collaborations. Research, education, and outreach are highly integrated by teaming graduate students with undergraduates, local high school teachers and underrepresented students. Educational media including instructional laboratory modules and course materials will be developed and disseminated broadly using the MITx/EdX online educational platform. This research program will provide a fundamental understanding of unconventional current-induced torques and chiral spin textures that arise in ultrathin ferromagnetic heterostructures with broken inversion symmetry and strong spin-orbit coupling. The program aims to (1) quantitatively and systematically characterize spin-orbit torques in ferromagnet/heavy metal bilayers to identify their dependence on interface materials and structure, (2) provide a mechanistic understanding of magnetization switching and magnetic domain wall motion in the presence of strong spin-orbit coupling, and (3) establish the materials design principles necessary to optimize these phenomena for spintronic devices. Experiments focus on transition metals and alloys that order well above room temperature, interfaced with nonmagnetic heavy metals and oxide dielectrics that are amenable to integration with conventional semiconductor fabrication processes. The intellectual merits of these fundamental studies include important new insights into surface and interface magnetism, the quantum-mechanical effects of broken symmetries in nanoscale systems, and coupling between the charge and spin degrees of freedom. The fundamental studies will lead to revolutionary new spin-based memory and logic device capabilities, offering enhanced performance and durability with ultralow power consumption requirements.