Spin Caloritronics and Skyrmion Materials

****技术摘要****该项目旨在研究实验凝聚态物理中的自旋热电子学和斯格明子材料这两个重要课题。在自旋热电子学中，人们利用热传输与电子的电荷/自旋自由度之间的相互作用。其中，自旋塞贝克效应（SSE）是少数几种无需充电电流即可产生纯自旋电流的方法之一，因此非常重要。人们提出了新的实验来捕获金属和绝缘体中横向和纵向配置的本征 SSE，分别具有面内和面外温度梯度，并开发了合适​​的自旋电流探测器。斯格明子材料是一种特殊的固体，不具有反演对称性，并且存在 Dzyaloshinskii-Moriya (DM) 相互作用，从而产生螺旋基态，更有趣的是，形成一种新颖的斯格明子自旋结构。外延斯格明子薄膜具有单晶或多晶材料无法达到的属性，将用于研究拓扑霍尔效应、贝里相引起的自旋电子效应、自旋极化电流引起的斯格明子晶格运动以及斯格明子材料中的能斯特效应。研究生、博士后和本科生，包括女性，都将参与这项研究。****非技术摘要****该项目旨在探索凝聚态物理中的自旋热电子学和斯格明子材料这两个新的重要课题。在自旋热电子学中，人们利用热流来产生自旋电流，而无需充电电流。 纯电流可以实现新的自旋电子现象，但产生的热量要少得多。自旋塞贝克效应（SSE）是少数新实现的可以产生纯自旋电流的方法之一。新的实验旨在捕获不同测量配置中的固有 SSE，识别可以检测纯自旋电流的材料，并将 SSE 与其他无关效应分开。 在常见的磁铁（包括冰箱磁铁）中，小磁矩是对齐的。 在一些被称为斯格明子材料的新型磁体中，磁矩不是对齐的，而是形成复杂的双扭曲结构，具有用于探索和开发的独特特性。斯格明子薄膜将用于追求新的物理效应，这些效应可用于新的设备应用，这可能有利于现有的数据存储技术，甚至可能启用新技术。

****Technical Abstract****This project seeks to pursue two important topics of spin caloritronics and Skyrmion materials in experimental condensed matter physics. In spin caloritronics, one exploits the interaction between heat transport and the charge/spin degree of freedom of electrons. Of those, spin Seebeck effect (SSE) is one of the few methods that can generate a pure spin current without a charge current, hence of great importance. New experiments have been proposed to capture the intrinsic SSE in both the transverse and the longitudinal configurations, with in-plane and out-of-plane temperature gradient respectively, in metals as well as insulators, and the development of suitable spin current detectors. Skyrmion materials are special solids without the inversion symmetry and with the presence of the Dzyaloshinskii-Moriya (DM) interaction, resulting a helical ground state, and more interestingly, a novel Skyrmion spin structure. Epitaxial Skyrmion thin films, with attributes unattainable in single crystals or polycrystalline materials, will be exploited to study the topological Hall effect, spintronic effects due to the Berry phase, motion of Skyrmion lattice by spin-polarized current, and the Nernst effect in Skyrmion materials. Graduate students, post-docs, and undergraduate students, including women, will be involved in the research.****Non-Technical Abstract****This project seeks to pursue two new and important topics of spin caloritronics and Skyrmion materials in Condensed Matter Physics. In spin caloritronics, one exploits heat flows to generate a spin current without an electric charge current. A pure current enables new spintronic phenomena but generates much less heat. Spin Seebeck effect (SSE) is one of the few newly realized methods that can generate a pure spin current. New experiments have been designed to capture intrinsic SSE in different measuring configurations, to identify materials that can detect a pure spin current, and to separate SSE from other extraneous effects. In common magnets, including refrigerator magnets, the small magnetic moments are aligned. In some new magnets, known as the Skyrmion materials, the magnetic moments are not aligned but form an intricate double-twist structure with unique properties for exploration and exploitation. Skyrmion thin films will be used to pursue new physical effects, which may be exploited for new device applications that may benefit existing data storage technology or may even enable new technologies.