Frustration through anisotropy in quantum magnets

量子磁铁各向异性带来的挫败感

• 批准号: RGPIN-2020-04970
• 负责人: Rau, Jeffrey
• 金额: $ 2.11万
• 依托单位: University of Windsor
• 依托单位国家: 加拿大
• 项目类别: Discovery Grants Program - Individual
• 财政年份: 2022
• 资助国家: 加拿大
• 起止时间: 2022-01-01 至 2023-12-31
• 项目状态: 已结题
• 来源: https://www.nserc-crsng.gc.ca/ase-oro/Details-Detailles_eng.asp?id=762561
• 关键词: Frustration; through; anisotropy; quantum; magnets

This research proposal aims to improve our theoretical understanding of magnetic materials. Such materials, and condensed matter physics more broadly, offer an unparalleled window into the realm of quantum and classical many-body phenomena. Through the study of such systems one can hope to understand the rich tapestry of emergent and collective behaviour that can lurk inside even everyday materials. In particular, we aim to improve our understanding of magnets that are both highly anisotropic and highly frustrated. Anisotropy, refers to the physics of the material being dependent on how the microscopic magnetic moments of the atoms are oriented relative to the crystal lattice -- a consequence of a relativistic effect, spin-orbit coupling. Frustration, refers to the incompatibility of multiple tendencies; when it is not possible to satisfy all of the interactions between the magnetic moments at the same time. Combining these two, frustration through anisotropy is when the origin of the frustration is due to the anisotropy in the magnetic interactions, and not, say, through the geometric arrangement of the atoms in the crystal. Through anisotropy, frustration can be generated in a rich variety of ways, each of which has the potential to lead to new and interesting phases of matter. This proposal attacks this topic from two different, but related, directions. First, we address the microscopic origins of magnetic interactions in one of the largest and most varied classes of anisotropic magnets, those where the magnetic ion is a rare-earth element. We will theoretically investigate what kinds of magnetic interactions are possible in a variety of different crystal lattices and structures that are relevant for real materials, with the goal of identifying new and unexplored kinds of frustration. Second, we will develop new methods for understanding the excitations of anisotropic magnets, i.e. the kinds of states they take on when they absorb energy, as happens when they are probed by light or neutrons in many experimental studies. This effort will be pursued though both a quantitative, computational perspective using a kind of series expansion technique, as well as via a more analytical, mathematical route involving the theory of systems that exhibit intrinsic loss or gain of particles. This research will be important for the theoretical and experimental condensed matter physics community, as it will provide new ways to understand known frustrated anisotropic materials, as well as motivate new materials to explore. These new materials, and an understanding of their physics, should provide insights into fundamental questions of classical and quantum many-body physics, and perhaps inspire new technological applications.

该研究建议旨在提高我们对磁性材料的理论理解。这样的材料和凝结物理物理学更广泛地为量子和经典多体现象的领域提供了无与伦比的窗口。通过对这样的系统的研究，人们可以希望了解即使是日常材料也可以潜伏在内部的新兴和集体行为的丰富挂毯。 特别是，我们旨在提高对高度各向异性且高度沮丧的磁铁的理解。各向异性是指材料的物理学取决于原子的显微镜磁矩相对于晶体晶格的定向，这是相对论效应，自旋轨道耦合的结果。挫败感是指多种趋势的不兼容。当无法同时满足磁矩之间的所有相互作用时。通过各向异性结合了这两个，挫败感是由于挫败感的起源是由于磁相互作用中的各向异性引起的，而不是通过晶体中原子的几何布置。通过各向异性，可以通过各种方式产生挫败感，每种方式都有可能导致物质的新阶段。 该建议从两个不同但相关的方向攻击了这个主题。首先，我们解决了最大和最多样化的各向异性磁体之一中磁相互作用的微观起源，其中磁离子是稀土元件。从理论上讲，我们将在各种与真实材料相关的不同晶体晶格和结构中可以研究哪种磁相互作用，目的是识别新的和未开发的挫败感。其次，我们将开发新的方法来理解各向异性磁铁的激发，即，在许多实验研究中被光或中子探测时，它们吸收能量时采取的状态种类。通过使用一种串联扩展技术的定量，计算观点，以及通过更具分析性的数学途径，涉及涉及表现出内在损失或粒子增益的系统理论，将实现这一努力。这项研究对于理论和实验性凝结物理学界将很重要，因为它将提供新的方法来了解已知的沮丧的各向异性材料，并激发新的材料探索。这些新材料以及对其物理学的理解应提供有关古典和量子多体物理学基本问题的见解，也许可以激发新的技术应用。