Collaborative Research: Design and Demonstration of Persistent Spin Textures in Ferroelectric Oxide Thin Film

现代电子学的基础是电子通过由硅等半导体制成的纳米级晶体管。计算能力的指数增长是通过缩小晶体管的尺寸和增加其密度来实现的。随着晶体管的尺寸接近原子尺度，进一步小型化是不可能的。计算和信息处理的另一种途径是利用自旋，这是基本粒子的一种固有属性。自旋电子公司将电子设备与Spin相结合，使信息处理和存储设备具有更高的能效和更少的热量产生。磁场的限制功能仍然是在磁性材料中跨纳米尺度传输自旋，而不会丢失存储的信息。该项目利用相对论量子力学效应--自旋-轨道相互作用--以及晶体对称性来保护自旋在非磁性材料中传播时的状态。该研究小组将把实验工作与模拟相结合，实现一种用于自旋电子学的新型薄膜氧化物材料。在整个项目中，多层次学生的教学和培训相互交织。该项目将通过公共宣传活动、课程开发和招募学生参与跨学科实验研究，扩大代表不足的学生对STEM的参与。教育影响延伸到高中教师，他们将被招募参与研究，并为他们的课堂开发材料物理模块。这些努力将赋予学生在STEM未来职业生涯中所需的解决问题的技能，从而影响下一代劳动力。识别超越摩尔定律的设备和技术的愿望促使人们越来越关注一系列替代计算设备，包括使用自旋而不是电子电荷。基于自旋轨道的电子学领域的一个限制特征是，很难从传统的半导体和磁性材料中获得长寿命和完全可控的自旋。这个项目的目标是设计、发现和展示铁电氧化物，它体现了一种对称保护的持久自旋织构，这使得编码在自旋中的信息在传播时对破坏是健壮的。该项目的独特之处在于利用原子拓扑在具有自旋-轨道相互作用的块状材料中实现新颖的自旋织构，而不是通过传统的量子井结构微妙地平衡多个难以控制的相互作用。该项目将理论、模拟和综合实验与复杂的薄膜氧化物生长方法相结合，以开发新的自旋织构理论和模型，识别和合成具有对称性决定自旋织构的新型铁电氧化物，并探索自旋织构的电场可调性。该项目的成果包括复杂材料中自旋织构的新描述和预测理论、新型复杂过渡金属氧化物铁电材料的实现以及基于自旋的设备的演示。该奖项反映了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。

Modern electronics are based on moving electrons through nanoscale transistors made of semiconductors such as silicon. The exponential growth in computing power has been realized by shrinking the size of transistors and increasing their density. As the dimensions of transistors approach atomic scales, further miniaturization is not possible. An alternative route to computing and information processing exploits spin, an intrinsic property of elementary particles. Spintronics combines electronics with spin, allowing for devices for information processing and storage that have superior energy efficiency and reduced heat-generation. The limiting feature for the field remains transporting spins across nanoscale dimensions in magnetic materials without losing the stored information. This project exploits a relativistic quantum mechanical effect – spin-orbit interaction – along with crystalline symmetries to protect the state of the spin as it travels in non-magnetic materials. The research team will combine experimental work with simulations to realize a new class of thin film oxide materials for spintronics. Teaching and training of students at multiple levels is interwoven throughout the project. The project will broaden STEM participation by underrepresented students through public outreach events, curriculum development, and recruiting students to participate in interdisciplinary experimental research. The educational impact extends to high-school teachers, who will be recruited to participate in research and develop materials physics modules for their classrooms. These efforts will impact the next-generation workforce by endowing students with the problem solving skills needed for future careers in STEM.The desire to identify beyond Moore’s Law devices and technologies has driven increasing attention on a range of alternative computing devices, including using the spin rather than the charge of an electron. The limiting feature for the field of spin-orbit-based electronics is the difficulty in attaining both long-lived and fully controllable spins from conventional semiconductor and magnetic materials. The goal of this project is to design, discover, and demonstrate ferroelectric oxides embodying a symmetry-protected persistent spin texture, which permits information encoded in the spins to be robust to corruption as they propagate. Unique to this project is the use of atomic topology to achieve the novel spin textures in bulk materials with spin-orbit interactions, rather than by delicately balancing multiple, hard to control, interactions through conventional quantum-well structures. The project couples theory, simulation, and comprehensive experimentation with sophisticated thin film oxide growth methods to develop new theories and models for spin textures, identify and synthesize novel ferroelectric oxides exhibiting symmetry-determined spin textures, and explore electric-field tunability of the spin textures. Outcomes of the project include new descriptive and predictive theories for spin textures in complex materials, realization of novel complex transition metal oxide ferroelectrics, and demonstration of spin-based devices.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.