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arXiv 2103.05656cond-mat.str-el
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自旋空间群与磁振子带拓扑

Spin-Space Groups and Magnon Band Topology

A. Corticelli, R. Moessner, P. A. McClarty

摘要:

能带拓扑结构既受到对称性的约束,又因对称性的存在而丰富。反幺正对称性的重要性,如时间反演,早在导致拓扑能带结构的分类的基础上的十倍的方式被认识。从那时起,晶格点群和非对称对称性被认为导致了大量可能的拓扑非平凡能带结构,其中许多是在材料中实现的。在本文中,我们表明,带拓扑结构进一步丰富了许多物理上可实现的情况下,磁和晶格自由度是完全或部分解耦。描述一般磁性系统的适当对称群是自旋空间群。在这里,我们描述的情况下,自旋空间群是必不可少的,以了解在磁性材料的能带拓扑结构。然后,我们专注于磁振子带拓扑结构的自旋空间群的理论有其最简单的实现。我们认为磁哈密顿与各种类型的耦合,包括海森堡和Kitaev耦合揭示了层次结构的增强磁对称群的性质取决于晶格和耦合。我们详细描述了相关的表示理论和兼容性关系,从而表征磁振子带上的强制约束,揭示了节点,线,平面和体积的扩散。

英文摘要:

Band topology is both constrained and enriched by the presence of symmetry. The importance of anti-unitary symmetries such as time reversal was recognized early on leading to the classification of topological band structures based on the ten-fold way. Since then, lattice point group and non-symmorphic symmetries have been seen to lead to a vast range of possible topologically nontrivial band structures many of which are realized in materials. In this paper we show that band topology is further enriched in many physically realizable instances where magnetic and lattice degrees of freedom are wholly or partially decoupled. The appropriate symmetry groups to describe general magnetic systems are the spin-space groups. Here we describe cases where spin-space groups are essential to understand the band topology in magnetic materials. We then focus on magnon band topology where the theory of spin-space groups has its simplest realization. We consider magnetic Hamiltonians with various types of coupling including Heisenberg and Kitaev couplings revealing a hierarchy of enhanced magnetic symmetry groups depending on the nature of the lattice and the couplings. We describe, in detail, the associated representation theory and compatibility relations thus characterizing symmetry-enforced constraints on the magnon bands revealing a proliferation of nodal points, lines, planes and volumes.

机构、总结、中文摘要均由AI分析而来,可能存在错误,请以论文正文为准。

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