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前所未有的水平，但由于电荷载流子运动产生的焦耳加热，微电子技术受到了严重阻碍。一种新的方法是在使用最少载流子的设备中利用纯自旋电流，从而在金属中产生最小的热量，在没有电荷载流子的磁性绝缘体中几乎不产生热量。自旋Seebeck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。仅在几年前才在实验中发现的SSE，已经催生了一个名为Spin Caloritronics的新兴领域，它为将废热转化为电能以及电子设备的热管理提供了新的策略。这个项目将通过密切的理论和实验互动，专注于对SSE效应的基本理解，并将探索新的铁磁和反铁磁绝缘体，以改进自旋热电子学现象和器件。技术描述：拟议的项目将结合理论、表征和材料合成工作，以更好地了解自旋热电子学现象和装置。这一努力将建立在三个关键和相互关联的要素之上。其中包括对自旋量热现象的物理和相关问题的理论理解、各种磁性和反铁磁绝缘体单晶的自旋量热学性质的测量，以及利用具有优异性能的材料制造自旋量热电子性薄膜器件。通过扩展自旋-轨道耦合是关键因素的拓扑绝缘体的丰硕研究成果和声子-磁振子相互作用理论，Fiete将发展一种微观理论来理解与自旋量热现象相关的物理现象。他还将开发用于筛选和设计制造自旋量热电子器件的新材料的计算工具。模拟工作将包括产生自旋电流的材料和将自旋电流高效转化为电势的金属材料以及接口设计。该项目将利用周在生长各种块状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、双季铵盐和焦绿石。在旋转量热电子学装置的计算筛选和设计中，优先考虑地球丰富的元素。高压合成可以克服材料合成中最具挑战性的问题，特别是在元素丰富的情况下。钱的实验室开发的自旋电子器件的程序、制造和测量技术将被用来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，并为进一步完善模型提供新的输入。在协同PI之间将形成迭代反馈回路。

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.