U.S.-Brazil Collaboration: Excitations in Two-Dimensional Magnets

9502781 Wysin美国-巴西合作研究基金将支持堪萨斯州立大学的Gary Wysin与米纳斯吉拉斯州联邦大学的A. S. T. Piers和M. E. Gouvea合作进行准二维磁体拓扑非线性激发特性的理论和计算分析。这项研究将扩展目前对这些系统中涡旋、孤子和自旋波激发特性的理解。拓扑激励的磁性将部分由精确已知解的微扰理论决定，部分由数值模拟决定。提出的研究将更好地理解构成二维磁体拓扑激励的特定自旋结构，以及确定激励的内部正常模式。一个重要的贡献将是表征拓扑激励在这种磁体相变中的作用。虽然拓扑缺陷已被证明是超流体和超导体、液晶和其他物理系统中相变的重要因素，但拟议的工作将对易平面和易轴二维磁体的这些影响进行研究。巴西团队带来了这类性质的分析研究经验，而美国团队则拥有同类性质的计算机模拟经验。＊＊＊

9502781 Wysin This U.S.-Brazil Collaborative Research grant will support the research of Gary Wysin, Kansas State University, in collaboration with A. S. T. Piers and M. E. Gouvea of the Universidade Federal de Minas Gerais to perform theoretical and computational analyses of the properties of topological nonlinear excitations in quasi-two-dimensional magnets. The research will extend the current understanding of the properties of the vortex, soliton, and spinwave excitations in these systems. The magnetic properties of topological excitations will be determined partly by perturbation theory from exactly known solutions, and partly by numerical simulations. The proposed studies will provide a better understanding of the particular spin structures that make up the topological excitations in two-dimensional magnets, as well as determine the internal normal modes of the excitations. An important contribution will be the characterization of the role of topological excitations in the phase transitions in such magnets. While topological defects have been shown to be significant factors in phase transitions in superfluids and superconductors, in liquid crystals, and in other physical systems, the proposed work will carry the investigation of these effects to easy-plane and easy-axis two-dimensional magnets. The Brazilian group brings experience in the analytical study of such properties, while the U.S. group has experience in computer simulation of the same class of properties. ***