Bottom-up design of spin-split and reshaped electronic band structures in antiferromagnets without spin-orbit coupling: Procedure on the basis of augmented multipoles
Bottom-up design of spin-split and reshaped electronic band structures in antiferromagnets without spin-orbit coupling: Procedure on the basis of augmented multipoles
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DOI：
10.1103/physrevb.102.144441
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发表时间：
2020-10-27
影响因子：
3.7
通讯作者：
Kusunose, Hiroaki
中科院分区：
文献类型：
--
作者：
Hayami, Satoru;Yanagi, Yuki;Kusunose, Hiroaki
我们提出了一种在自旋轨道耦合自由反铁磁体中具有固有自旋和动量依赖性的电子能带结构的有效微观设计程序。我们用于创建所需的自旋分裂和重塑电子能带结构的自下而上的设计方法可能会导致进一步发现实用的自旋轨道耦合自由材料，由于这种能带结构而表现出巨大的自旋相关和/或非互易输运、磁电和弹性响应等。我们建立了一个系统指南，通过使用两个极多极自由度（即电和磁环形多极）在自旋轨道耦合自由系统中构建对称/反对称自旋分裂和反对称变形的自旋独立能带结构。两个极多极子构成一个完整的集合，描述了跳跃哈密顿量中的任意自由度，其在团簇中的在位和离位自由度分别被描述为所谓的团簇和键多极子，而团簇之间连接的另一个自由度被表示为动量多极子。通过使用这些多极描述，我们阐明了在磁有序状态下实现本征带变形的简单微观条件：当簇和键多极包含相同的多极对称性时，在共线磁体中实现对称自旋分裂。当存在键合型磁性环形多极时，反对称自旋分裂发生在非共线反铁磁体中。此外，在非共面反铁磁体中实现了具有自旋简并的反对称能带变形。我们举例说明了由三角形单元、三角形、戈薇和呼吸戈薇结构形成的三个晶格系统，以演示磁有序下的能带变形。在所提出的程序的基础上，我们根据磁性结构数据库 MAGNDATA 列出了显示本征能带变形的各种候选材料。
We propose an efficient microscopic design procedure of electronic band structures having intrinsic spin and momentum dependences in spin-orbit-coupling free antiferromagnets. Our bottom-up design approach to creating desired spin-split and reshaped electronic band structures could result in further findings of practical spin-orbit-coupling free materials exhibiting a giant spin-dependent and/or nonreciprocal transport, magnetoelectric and elastic responses, and so on, as a consequence of such band structures. We establish a systematic guideline to construct symmetric/antisymmetric spin-split and antisymmetrically deformed spin-independent band structures in spin-orbit-coupling free systems by using two polar multipole degrees of freedom, i.e., electric and magnetic toroidal multipoles. The two polar multipoles constitute a complete set and describe arbitrary degrees of freedom in the hopping Hamiltonian, whose onsite and offsite degrees of freedom in a cluster are described as the so-called cluster and bond multipoles, respectively, and another degree of freedom connecting between clusters is expressed as momentum multipoles. By using these multipole descriptions, we elucidate simple microscopic conditions to realize intrinsic band deformations in magnetically ordered states: The symmetric spin splitting is realized in collinear magnets when cluster and bond multipoles contain the same symmetry of multipoles. The antisymmetric spin splitting occurs in noncollinear antiferromagnets when a bond-type magnetic toroidal multipole is present. Furthermore, the antisymmetric band deformation with spin degeneracy is realized in noncoplanar antiferromagnets. We exemplify three lattice systems formed by a triangle unit, triangular, kagome, and breathing kagome structures, to demonstrate the band deformations under the magnetic ordering. On the basis of the proposed procedure, we list up various candidate materials showing intrinsic band deformations in accordance with MAGNDATA, magnetic structures database.