Collaborative Research: Spin Transport in Nonrelatisvistically Spin-split Antiferromagnets

非技术性总结在1970年的诺贝尔奖演讲中，路易斯·内尔曾将反铁磁体--附近原子的磁矩方向相反的材料--描述为有趣但无用。这是由于它们的净磁矩消失，这使得反铁磁体的性质很难通过外加磁场来控制。向前跳跃50年，在商业存储应用中，反铁磁体已经成为铁磁体的潜在替代品--原子磁矩方向相同的材料。与铁磁体不同，反铁磁体可以将速度和存储密度提高数量级。然而，利用这种潜力需要为反铁磁体开发有效的信息写入和读出协议，这比用于铁磁体的协议更具挑战性。该项目通过利用一类新发现的反铁磁体的独特性质来解决这一挑战，这些反铁磁体沿某些晶体方向显示出未补偿的磁矩。在这些反铁磁体的净磁矩保持为零的情况下，如果已经成功地开发了生长这些反铁磁体的单晶膜的方法，则该特性允许与用于铁磁体的那些类似的信息写入和读出协议。这个合作项目汇集了特拉华大学和内布拉斯加-林肯大学的实验和理论专业知识，最终目标是开发基于这种新型反铁磁体的存储单元。这项合作研究将阐明这种新型反铁磁体的独特性质，并有可能给信息处理和存储带来革命性的变化。该项目将为早期职业团队成员提供宝贵的现代实验和理论方法培训，为他们从事材料科学的尖端研究做好准备。该项目强调吸纳来自代表人数不足的少数群体的学生，使他们有机会接触高级跨学科学习，并丰富他们的专业准备。研究团队将与提供智力刺激和关于行业职业机会的重要教育组成部分的行业研究人员合作。利用特拉华大学现有的项目，该团队将拓展到高中，吸引少数族裔高中生，并激发他们对科学和工程的兴趣。此外，团队成员将积极参与由NSF资助的内布拉斯加-林肯大学和塔斯基吉大学之间的材料研究和教育伙伴关系(PREM)计划。建议的研究结果将通过现代多媒体渠道传播给更广泛的受众，包括由NSF支持的在线资源FunSize Physics。技术总和反铁磁体由于其数量级提高的开关速度和存储密度，在自旋电子器件应用中具有取代铁磁体的巨大潜力。要实现这一势，需要发展有效的电控制和反铁磁有序参数的检测，即Néel矢量，这比控制和检测铁磁中的磁化强度更具挑战性。这一提议通过利用反铁磁性材料的独特性质来解决这一挑战，这些材料属于支持动量依赖自旋分裂的空间群。其中包括RuO2--室温反铁磁金属，它的电子能带沿某些晶体方向发生自旋分裂。该提议需要实验和理论研究的共同努力，目的是利用这些非相对论自旋分裂反铁磁体提供的优势。最终目标是演示Néel矢量的电控制和检测，最终实现在室温下具有大隧道磁阻的全功能反铁磁隧道结。通过从根本上提高我们对这些现象背后的物理和材料科学的理解，拟议的研究将有助于开发性能优越的自旋电子器件。研究团队将与行业研究人员合作，为行业潜在的职业机会提供智力刺激和有价值的见解。此外，该项目将为早期职业团队成员提供现代实验和理论方法方面的必要技能，这对于在材料科学前沿进行研究至关重要。该项目强调吸纳来自代表人数不足的少数群体的学生，使他们有机会接触高级跨学科学习，并丰富他们的专业准备。利用特拉华大学现有的项目，该团队将接触到高中，吸引少数族裔高中生，并激发他们对科学和工程的兴趣。此外，团队成员将积极参与由NSF资助的内布拉斯加州林肯大学和塔斯基吉大学之间的材料研究和教育伙伴关系(PREM)计划。建议的研究结果将通过现代多媒体渠道向更广泛的受众传播，包括由NSF支持的在线资源FunSize Physics。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。

NON-TECHNICAL SUMMARYIn his 1970 Nobel Prize Lecture, Louis Néel famously described antiferromagnets – materials with nearby magnetic moments of atoms being oriented in opposite directions, as interesting but useless. This is due to their vanishing net magnetic moment which makes difficult to control properties of antiferromagnets by an applied magnetic field. Jump forward 50 years, antiferromagnets have emerged as potential replacements for ferromagnets – materials with magnetic moments of atoms being oriented in the same direction, in commercial memory applications. Unlike ferromagnets, antiferromagnets can improve speed and storage density by orders of magnitude. However, harnessing this potential requires the development of efficient information write and read-out protocols for antiferromagnets, which is much more challenging than those used for ferromagnets. This project addresses this challenge by exploiting unique properties of a newly discovered class of antiferromagnets that exhibit an uncompensated magnetic moment along certain crystal directions. While the net magnetic moment of these antiferromagnets remains vanishing, this property allows similar information write and read-out protocols as those used for ferromagnets, provided that the methods to grow single-crystal films of these antiferromagnets have been successfully developed. This collaborative project brings together the experimental and theoretical expertise of the University of Delaware and University of Nebraska-Lincoln with the ultimate goal of developing a memory cell based on this new class of antiferromagnets. The collaborative research will elucidate the unique properties of this new class of antiferromagnets and holds potential to revolutionize information processing and storage. The project will provide valuable training in modern experimental and theoretical methods for early career team members, preparing them for cutting-edge research in materials science. The project emphasizes the inclusion of students from underrepresented minority groups, providing them with exposure to advanced interdisciplinary studies and enriching their professional preparation. The research team will collaborate with industrial researchers offering intellectual stimulus and an important educational component regarding career opportunities in industry. Leveraging the existing program at University of Delaware, the team will outreach to high schools, engaging minority high-school students and inspiring their interest in science and engineering. Additionally, team members will actively participate in the NSF-funded Partnerships for Research and Education in Materials (PREM) program between the University of Nebraska-Lincoln and Tuskegee University. Results of the proposed research will be disseminated to a broader audience via modern multimedia channels including an NSF-supported online resource Funsize Physics.TECHNICAL SUMMARYAntiferromagnets hold great potential for replacing ferromagnets in spintronic device applications due to their orders of magnitude enhanced switching speed and storage density. Realizing this potential requires the development of efficient electric control and detection of the antiferromagnets order parameter, known as the Néel vector, which is much more challenging than the control and detection of the magnetization in ferromagnets. This proposal addresses this challenge by exploiting unique properties of the antiferromagnetic materials that belong to a space group supporting momentum-dependent spin splitting. Among them is RuO2 – the roomtemperature antiferromagnetic metal, exhibiting spin splitting of its electronic bands along certain crystallographic directions. The proposal entails a collaborative effort involving experimental and theoretical research, with the goal of harnessing the advantages offered by these nonrelativistically spin-split antiferromagnets. The ultimate goal is to demonstrate the electrical control and detection of the Néel vector, culminating in the realization of a fully functional antiferromagnetic tunnel junction with a large tunneling magnetoresistance at room temperature. By fundamentally advancing our understanding of the physics and materials science underlying these phenomena, the proposed research will contribute to the technological development of spintronic devices with superior performance. The research team will collaborate with industrial researchers providing intellectual stimulus and valuable insights into potential career opportunities in industry. Additionally, the project will equip early career team members with necessary skills in modern experimental and theoretical methods, essential for conducting research at the frontiers of materials science. The project emphasizes the inclusion of students from underrepresented minority groups, providing them with exposure to advanced interdisciplinary studies and enriching their professional preparation. Leveraging the existing program at University of Delaware, the team will reach out to high schools, engaging minority high-school students and inspiring their interest in science and engineering. Furthermore, team members will actively participate in the NSF-funded Partnerships for Research and Education in Materials (PREM) program between University of Nebraska-Lincoln and Tuskegee University. Results of the proposed research will be disseminated to a broader audience via modern multimedia channels including an NSF-supported online resource Funsize Physics.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.