Spin Caloritronics and Skyrmion Materials

* 技术摘要 * 本项目旨在研究实验凝聚态物理中的自旋热电子学和Skyrmion材料这两个重要课题。在自旋热电子学中，人们利用热传输和电子的电荷/自旋自由度之间的相互作用。其中，自旋塞贝克效应（SSE）是少数几种可以产生纯自旋电流而不需要电荷流的方法之一，因此非常重要。已经提出了新的实验来捕获的内在SSE在横向和纵向配置，分别与平面内和平面外的温度梯度，在金属以及绝缘体，和合适的自旋电流检测器的发展。Skyrmion材料是一种特殊的固体，没有反转对称性，并且存在Dzyaloshinskiii-Moriya（DM）相互作用，导致螺旋基态，更有趣的是，一种新的Skyrmion自旋结构。Skyrmion外延薄膜具有单晶或多晶材料无法达到的属性，将被用来研究拓扑霍尔效应，由于Berry相的自旋电子效应，自旋极化电流引起的Skyrmion晶格运动，以及Skyrmion材料中的能斯特效应。研究生，博士后和本科生，包括女性，将参与研究。非技术摘要 * 本项目旨在追求两个新的和重要的主题自旋热电子学和Skyrmion材料在凝聚态物理。在自旋热电子学中，人们利用热流来产生自旋电流，而不需要电荷电流。 纯电流能够产生新的自旋电子现象，但产生的热量要少得多。自旋塞贝克效应（SSE）是近年来出现的几种产生纯自旋流的方法之一。新的实验已经被设计成在不同的测量配置中捕获内在SSE，以确定可以检测纯自旋电流的材料，并将SSE与其他外来效应分离。 在普通磁体中，包括冰箱磁体，小磁矩是对齐的。 在一些被称为Skyrmion材料的新磁体中，磁矩并不对齐，而是形成一种复杂的双扭曲结构，具有独特的勘探和开发特性。Skyrmion薄膜将用于追求新的物理效应，这可能会被用于新的设备应用，这些应用可能会使现有的数据存储技术受益，甚至可能实现新的技术。

****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.