Magneto-Thermo-Electric Effects In Antiferromagnetic Spintronics

本项目将识别和开发复杂反铁磁体（AF）中的新型输运机制。我们将专注于晶体，拓扑，和异常的自旋霍尔效应，自发霍尔效应（HE）和他们的热对应物（能斯特效应）的起源，所产生的部分自发对称性破缺AF。该项目解决了自旋电子学新兴分支中的基本问题，该分支基于晶体对称性、拓扑结构及其与AF顺序的相互作用所支配的输运现象。这种结合可能被证明是必不可少的发展强大的大效应至关重要的新器件概念在非常活跃的领域AF spintronics.In自旋电子学领域，电荷和自旋电流之间的相互转换促进了基础物理的进步，并培育了新的应用的出现。在过去的十年里，人们发现负责自旋-电荷转换的主要机制，自旋HE（SHE），以各种方式揭示自己。实际上，HE要么与外在或内在自旋轨道耦合时的自旋偏转（“异常”HE、AHE）相关，要么与非平凡自旋结构（“拓扑”HE、THE）相关，要么与打破时间和空间反转对称组合的特定原子排列（“晶体”HE、CHE）相关。AF是研究这些不同机制的绝佳平台，以及它们的热（能斯特）对应物，这些机制是由它们的能带和自旋结构的相互作用引起的。请注意，CHE尚未在实验中观察到，晶体能斯特物理也根本没有得到解决。因此，这些影响是我们提案的重点。该项目的另一个关键特征在于材料（Mn 5Si 3）的选择，该材料将作为研究上述机制的多功能平台。采用Mn_5Si_3（AF）的变磁相变（65 K以下具有手征自旋结构，65 K以上具有共线自旋结构）。 AG.，以证明和控制CHE和THE及其热对应物的相对贡献。这种方法基于对模型系统的系统研究，是解开霍尔和能斯特响应起源的关键。因此，所提出的研究计划响应了对新知识和实验设计的需求，这些知识和实验设计对于更好地理解、解开和利用这些效应是必不可少的。- 实验观察并理论建模具有不同非平凡自旋结构、晶体取向的Mn 5Si 3中的CHE、THE和其他霍尔效应以及能斯特效应，和弹性应变; -测试假设的有效性和普遍性之间的莫特关系的电荷和热输运AF与非平凡的拓扑结构;-调查的影响逆SHE由非线性自旋波动附近的磁相变，并利用这种效果来探测磁序参数的变化。

This project will identify and exploit novel transport mechanisms in complex antiferromagnets (AFs). We will focus on crystalline, topological, and anomalous origins of the spin Hall effect, spontaneous Hall effect (HE) and their thermal counterparts (Nernst effects), arising in part by the spontaneous symmetry breaking in AFs. The project addresses fundamental questions in an emerging branch of spintronics based on transport phenomena governed by crystal symmetry, topology, and its interplay with AF order. This combination could prove essential for the development of robust large effects vital in new device concepts in the very active field of AF spintronics.In the field of spintronics, the inter-conversion between charge and spin currents has facilitated the progress of fundamental physics and fostered the emergence of new applications. In the past decade, it has emerged that the chief mechanism responsible for spin-charge conversion, the spin HE (SHE), reveals itself under various flavors. Indeed, HEs are either associated to the spin deflection upon extrinsic or intrinsic spin-orbit coupling ("anomalous" HE, AHE), to the non-trivial spin structures ("topological" HE, THE), or to specific atomic arrangements that break time- and spatial-reversal symmetry combinations ("Crystal" HE, CHE). AFs are excellent platforms to investigate these different mechanisms, and their thermal (Nernst) counterparts, arising from the interplay of their band and spin structures.Note that the CHE has not yet been observed in experiment, and that crystal Nernst physics has not been addressed at all. Therefore, these effects are a key focus of our proposal. Another key feature of the project lies in the choice of the material (Mn5Si3) that will serve as a versatile platform to investigate the above mechanisms. The metamagnetic phase transition of Mn5Si3 (AF with a chiral spin structure below 65K and collinear above) will be used, e. ag., to demonstrate and control the relative contributions of CHE and THE, and their thermal counterparts, respectively. This approach, based on the systematic study of a model system, is key to disentangle the origins of the Hall and Nernst responses. The proposed research program thus responds to the need for new knowledge and experimental designs that are essential to better understand, disentangle,nd take advantage of these effects.The key aims of this program are to:- grow high-quality ordered Mn5Si3 thin films;- experimentally observe and theoretically model the CHE, THE and other Hall as well as Nernst effects in Mn5Si3 with different non-trivial spin structures, crystal orientations, and elastic strain; - test the assumed validity and universality of the Mott relation between charge and thermal transport in AFs with non-trivial topology;- investigate the impact on the inverse SHE by non-linear spin fluctuations near magnetic phase transitions, and exploit this effect to probe the magnetic order parameter variations.