CHIME — CHirality-Induced dynamics of Magnetization and Electrons

CHIME â CHirality 诱发的磁化和电子动力学

• 批准号: 399448442
• 负责人: Professor Dr. Jairo Sinova, Ph.D.
• 金额: --
• 依托单位: Institut für Physik
• 依托单位国家: 德国
• 项目类别: Research Grants
• 财政年份: 2018
• 资助国家: 德国
• 起止时间: 2017-12-31 至 2021-12-31
• 项目状态: 已结题
• 来源: https://gepris.dfg.de/gepris/projekt/399448442?language=en
• 关键词: CHIME; CHirality; Induced; dynamics; Magnetization

The proposed research project aims to explore dynamical properties of chiral magnetic systems, which are relevant new materials for possible future device applications. The exponential increase on information storage demand has increased the need to find new paradigms of information storage devices. Currently information storage devices are either volatile (e.g. random access memory) or limited in performance (e.g. hard disk drive). Electric control of magnetization has been the focus for possible applications in the next generation devices that are non-volatile with high performance. A recent breakthrough arising from spin-orbit coupling and broken inversion symmetry, has given rise to new chiral electronic states and new phenomena that are forbidden in symmetric systems. Besides the fundamental interest in understanding these new phenomena, it has been demonstrated that it raises the energy efficiency significantly when manipulating magnetic textures affected by this chirality. Previous research has taken mostly either a top-down or a bottom-up approach. A top-down approach is to observe phenomenology first and then introduce phenomenological terms to describe it, but this does rarely allow microscopic understanding. On the other hand, a bottom-up approach is to carry out a first-principles calculation to make a prediction, but its dependence on system parameters makes it difficult to provide a general understanding. The goal of CHIME is to provide an efficient bridge between the two approaches, by providing theoretical descriptions that are concise, unified, general, and easily accessible to experimentalists. Examples of the target phenomena include spin-orbit torque, motion of topological textures, anisotropic magnetoresistance, and spin waves. We seek a model that is simple but still includes all the core microscopic ingredients, of which the parameters can be used as fitting parameters in experiment as well as be obtained by the first-principles calculations for direct predictability and material design power. In this way, we will be able to raise both microscopic and phenomenological understanding of chiral magnets and find an optimized structure for device applications. Our analytic results will be supported by collaboration with numerical simulations done by other members of my group. Concerning experiments we plan to exploit our fruitful collaboration with the in-house group and other external collaborators in Prague, Cambridge, and Kaiserslautern. We plan to generalize our formalism to other systems of recent interest, such as topological insulators, antiferromagnets, ferrimagnets, and superconducting two-dimensional states at interfaces where spin-orbit coupling and broken symmetry play crucial roles.

拟议的研究项目旨在探索手性磁系统的动力学特性，这是未来可能的设备应用的相关新材料。信息存储需求的指数级增长增加了寻找新的信息存储设备范例的需求。当前的信息存储设备要么是易失性的（例如随机存取存储器），要么是性能有限的（例如硬盘驱动器）。磁化的电控制一直是下一代非易失性高性能设备中可能应用的焦点。最近由于自旋轨道耦合和反演对称性破缺而取得的突破，产生了新的手性电子态和对称系统中禁止的新现象。除了理解这些新现象的基本兴趣之外，已经证明，在操纵受这种手性影响的磁性纹理时，它可以显着提高能量效率。以前的研究大多采用自上而下或自下而上的方法。自上而下的方法是首先观察现象学，然后引入现象学术语来描述它，但这很少允许微观理解。另一方面，自下而上的方法是进行第一性原理计算来进行预测，但其对系统参数的依赖使得很难提供一般性的理解。 CHIME 的目标是通过提供简洁、统一、通用且易于实验者理解的理论描述，在两种方法之间提供有效的桥梁。目标现象的示例包括自旋轨道扭矩、拓扑纹理的运动、各向异性磁阻和自旋波。我们寻求一个简单但仍包含所有核心微观成分的模型，其参数可以用作实验中的拟合参数，也可以通过第一性原理计算获得，以实现直接预测性和材料设计能力。通过这种方式，我们将能够提高对手性磁体的微观和现象学理解，并找到适合设备应用的优化结构。我们的分析结果将得到与我小组其他成员进行的数值模拟合作的支持。关于实验，我们计划利用与布拉格、剑桥和凯泽斯劳滕的内部团队和其他外部合作者的富有成效的合作。我们计划将我们的形式主义推广到最近感兴趣的其他系统，例如拓扑绝缘体、反铁磁体、亚铁磁体以及自旋轨道耦合和破缺对称性发挥关键作用的界面处的超导二维态。