FRUSTRATED MAGNETISM IN SPIN-ORBIT COUPLED MATERIALS

技术总结该奖项支持旨在实现对各种受挫量子磁体的基本了解的理论研究，包括局部和巡回类型的量子磁体。它包括三个研究方向：(1)研究受挫反铁磁体的磁化过程的异常特征，特别是强相关但巡回的三角形晶格上电子系统中磁化平台相的出现和稳定性。Pi和他的团队将研究在固定磁化强度下到金属状态的转变，并探索分离共面和锥形相的量子临界点对交换各向异性、自旋之间的层间相互作用以及微观自旋的大小的敏感性。(2)第二个方向致力于利用在感兴趣的实验材料中总是存在的自旋-轨道相互作用，以探索自旋-液体基态的分数自旋激发。(3)第三个方向是发展和应用一种新的数值方法，称为图解蒙特卡罗方法，用于研究受挫反铁磁体的有限温度性质。这种方法没有有限尺寸效应，而有限尺寸效应严重限制了更传统的数值方法，并有望为描述与实验相关的材料的合作顺磁状态开辟一条新的途径。该奖项还支持PI与概述的研究计划密切相关的教育活动。其中包括对分析和数值凝聚态物理的研究生和本科生的培训和教育。此外，国际物理研究所将开发一门新的研究生课程，现代材料物理学，旨在让学生接触凝聚态物理的最新发展。PI将继续维护一个研究网站，总结研究生和专业同事可访问的主要研究进展。非技术总结该奖项支持旨在实现对“受挫”磁性材料的基本理解的理论研究。挫折感是一个术语，用来描述不同的微观元素，如磁性材料内部的微观磁矩，无法找到组合中所有成员的可能能量贡献最小的平衡配置的情况。因此，有限部分的微观时刻可以被视为一直在“移动”，以寻找更令人满意的安排，而这种安排永远不会实现。这种情况导致了非常不寻常的磁结构和特殊的量子动力学的出现，它在广泛的温度、磁场和其他实验控制的外部参数范围内持续存在。PI将使用分析方法和开发新的数值技术来探索各种基本重要的受阻磁体系统。该奖项还支持与概述的研究计划密切相关的PI的教育活动。其中包括对分析和数值凝聚态物理的研究生和本科生的培训和教育。此外，国际物理研究所将开发一门新的研究生课程，现代材料物理学，旨在让学生接触凝聚态物理的最新发展。国际和平研究所将继续维持一个研究网站，其中概述了研究生和专业同事可查阅的主要研究进展。

TECHNICAL SUMMARYThis award supports theoretical research aimed at achieving a fundamental understanding of various frustrated quantum magnets, both of localized and itinerant kind. It consists of three research directions:(1) The first addresses the unusual features of the magnetization process of frustrated antiferromagnets, and in particular the appearance and the stability of magnetization plateau phases in the system of strongly correlated, but itinerant, electrons on a triangular lattice. The PI and his group will study the transition to the metallic state at fixed magnetization and explore the sensitivity of the quantum critical point separating the co-planar and cone phases with respect to exchange anisotropy and interlayer interactions between spins as well as the magnitude of the microscopic spin. (2) The second direction is devoted to exploiting spin-orbital interactions, which are always present in experimental materials of interest, in order to probe fractionalized spinon excitations of the spin-liquid ground states. (3) The third direction consists of the development and application of a novel numerical approach, called Diagrammatic Monte Carlo, to finite temperature properties of frustrated antiferromagnets. This method is free from the finite-size effect which severely restricts more traditional numerical approaches and is expected to open a new route for describing the cooperative paramagnetic states of experimentally relevant materials.This award also supports the PI's educational activities that are closely tied with the outlined research plan. These include the training and education of graduate and undergraduate students in analytical and numerical condensed matter physics. In addition, the PI will develop a novel graduate course, Physics of Modern Materials, that is aimed at exposing the students to newest developments in condensed matter physics. The PI will continue to maintain a research website which summarizes the main research developments in terms accessible to graduate students as well as to professional colleagues.NON-TECHNICAL SUMMARYThis award supports theoretical research aimed at achieving a fundamental understanding of "frustrated" magnetic materials. Frustration is a technical term used to describe situations when different microscopic elements, such as microscopic magnetic moments inside a magnetic material, are unable to find equilibrium configurations in which all members of the ensemble have minimal possible energy contributions. Thus, a finite fraction of microscopic moments can be viewed as being constantly "on the move" to look for a more satisfactory arrangement, which never materializes. This situation leads to the appearance of very unusual magnetic structures and peculiar quantum dynamics which persists over a wide range of temperatures, magnetic fields and other experimentally controlled external parameters. The PI will use analytical methods and develop new numerical techniques to explore a variety of fundamentally important frustrated magnet systems. This award also supports the PI's educational activities that are tied closely with the outlined research plan. These include the training and education of graduate and undergraduate students in analytical and numerical condensed matter physics. In addition, the PI will develop a novel graduate course, Physics of Modern Materials, that is aimed at exposing the students to newest developments in condensed matter physics. The PI will continue to maintain a research website which summarizes the main research developments in terms accessible to graduate students as well as to professional colleagues.