论文标题

手性多Q和天际阶段是由Rashba-Hund相互作用在Kagome晶格中引起的

Chiral multiple-q and skyrmion phases induced by Rashba-Hund interactions in the kagome lattice

论文作者

Villalba, M. E., Albarracín, F. A. Gómez, Cabra, D. C., Rosales, H. D.

论文摘要

由于其潜在的技术应用,在过去十年中,材料中的工程非微不足道的拓扑阶段(特别是天空状的布置)引起了人们的极大兴趣。在这项工作中,我们研究了一个电子模型,该模型通过RASHBA旋转轨道耦合在巨大的Hund相互作用极限中与磁矩相互作用的Kagome晶格中的磁纹理。我们获得了有效的自旋汉密尔顿,并使用大型蒙特卡洛模拟研究了外部磁场下的新兴低温阶段。我们表明,强烈的几何挫败感,kagome晶格的特征以及有效交换,反对称和各向异性耦合之间的竞争会引起各种各样的非平地拓扑阶段。一方面,对于抗铁磁交换耦合,伪抗磁磁性的天际晶体稳定在广泛的参数中。随着交换耦合的变小,手性单Q和双Q相出现。另一方面,在铁磁案例中,即使不同相互作用的竞争产生了一系列外来纹理,但可以使用具有反对称相互作用的纯铁磁模型来绘制出显着的平行。最后,对于完全抑制交换耦合的特殊情况,我们表明,来自较高温度合作的paramagnet,外部磁场引起了具有半遗传性退化性的“伞状” plaquette阶。

Engineering non trivial topological phases in materials, specially skyrmion-like arrangements, has been of great interest in the last decade due to its potential technological applications. In this work, we study a model of electrons coupled to a magnetic texture in the kagome lattice interacting with magnetic moments via Rashba spin orbit coupling in the large Hund interaction limit. We obtain the effective spin Hamiltonian and study the emergent low temperature phases under an external magnetic field using large scale Monte Carlo simulations. We show that strong geometric frustration, characteristic of the kagome lattice, and the competition between the effective exchange, antisymmetric and anisotropic couplings, gives rise to a large variety of non-trivial topological phases. On the one hand, for antiferromagnetic exchange coupling a pseudo-antiferromagnetic skyrmion crystal is stabilized for a broad range of parameters. As the exchange coupling gets smaller, chiral single-q and double-q phases emerge. On the other hand, in the ferromagnetic case, even though the competition of the different interactions produce a series of exotic textures, a remarkable parallel may be drawn with the pure ferromagnetic model with antisymmetric interactions. Finally, for the special case where the exchange coupling is completely suppressed, we show that, coming from a higher temperature cooperative paramagnet, an "umbrella-like" plaquette order with semiextensive degeneracy is induced by the external magnetic field.

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