DMREF: Collaborative Research: Design and synthesis of novel materials for spin caloritronic devices

非技术描述：微电子学将现代技术推向了前所未有的水平，但由于电荷载流子运动产生的强烈焦耳热而受到严重阻碍。 一种新的方法利用了使用最少电荷载流子的设备中的纯自旋电流，从而在金属中产生最小的热量，而在不含电荷载流子的磁性绝缘体中几乎没有热量。 自旋塞贝克效应（SSE）允许人们从磁绝缘体中的温度梯度产生纯自旋电流。仅在几年前通过实验发现的SSE已经导致了一个新兴的新领域，称为自旋热电子学，它为废热转化为电力以及电子设备中的热管理提供了新的策略。这个项目，通过密切的理论/实验相互作用，将侧重于SSE效应的基本理解，并将探索新的铁磁和反铁磁绝缘体，以推进自旋热电子现象和设备。技术说明：拟议的项目将结合联合收割机理论，表征和材料合成的努力，以更好地了解自旋热电子现象和设备。 这一努力将建立在三个相互关联的关键要素之上。这些包括物理学的理论理解和与自旋热电子现象相关的问题，测量各种各样的磁性和反铁磁绝缘体单晶的自旋热电子特性，以及利用具有上级特性的材料制造自旋热电子薄膜器件。 通过扩展拓扑绝缘体的自旋-轨道耦合是一个关键因素和声子-磁振子相互作用理论的富有成效的研究，Fiete将开发一个微观理论，用于理解与自旋热电子现象相关的物理学。 他还将开发用于筛选和设计制造自旋热电子器件的新材料的计算工具。模拟工作将涵盖产生自旋电流的材料和将自旋电流高效转换为电势的金属材料以及界面设计。该项目将利用周在生长各种大块单晶方面的丰富经验和专业知识，包括亚铁磁性稀土铁石榴石，双钙钛矿，尖晶石，反铁磁性层状材料，具有独特的磁性，如单轴，易平面，biskyrmion和pyroxysteres。地球丰富的元素在自旋热电子器件的计算筛选和设计中被优先考虑。材料合成中最具挑战性的问题，特别是地球丰富的元素，可以通过高压合成来克服。 在钱的实验室开发的自旋电子器件的程序，制造和测量技术将用于研究由这些新材料制成的自旋热电子器件的性能。实验结果将与计算模型进行比较，并提供新的输入，以进一步完善模型。一个迭代的反馈回路将在共同PI之间形成。

Non-technical Description: Microelectronics, which has propelled modern technologies to unprecedented levels, has been severely hampered by the intense Joule heating generated by the motion of electrical charge carriers. A new approach exploits pure spin currents in devices that use a minimum of electrical charge carriers, thus generating minimal heat in metals and virtually no heat in magnetic insulators, which are charge-carrier free. The spin Seebeck effect (SSE) allows one to generate a pure spin current from a temperature gradient in a magnetic insulator. The SSE, experimentally discovered only a few years ago, has lead to a burgeoning new field known as spin caloritronics, which offers new strategies for the conversion of waste heat to electricity as well as thermal management in electronic devices. This project, through close theory/experiment interactions, will focus on the fundamental understanding of the SSE effect and will explore new ferromagnetic and antiferromagnetic insulators for advancing spin caloritronic phenomena and devices. Technical Description: The proposed project will combine theory, characterization, and materials synthesis efforts to better understand spin caloritronic phenomena and devices. The effort will be built on three key and interlocking elements. These include a theoretical understanding of the physics and issues associated with the spin caloritronic phenomena, measurement of spin caloritonic properties of a broad variety of single crystals of magnetic and antiferromagnetic insulators, and the fabrication of spin caloritronic thin films devices exploiting materials with superior properties. By extending the fruitful research on topological insulators where the spin-orbit coupling is a critical factor and the theory of phonon-magnon interaction, Fiete will develop a microscopic theory for understanding physics associated with spin caloritronic phenomena. He will also develop computational tools for screening and designing new materials for fabrication of spin caloritronic devices. The simulation work will cover the materials for generating spin current and metallic materials to convert spin current into electric potential with a high efficiency as well as the interface design. The project will capitalize on the extensive experience and expertise of Zhou in growing a broad range of bulk single crystals including ferrimagnetic rare earth iron garnets, double perovskites, spinels, antiferromagnetic layered materials with peculiar magnetic properties like uniaxial, easy-plane, biskyrmion, and pyrochlores. Earth abundant elements are prioritized in the computational screening and design for the spin caloritronic devices. The most challenging problems in the material synthesis, especially with Earth abundant elements, could be overcome by high-pressure synthesis. The procedures, the fabrication, and measurement techniques for spintronic devices developed in Chien's laboratory will be used to study the performance of spin caloritronic devices made from these new materials. The experimental results will be compared with the computational model and provide new inputs to further refine the model. An iterative feedback loop will be formed among the co-PIs.