Stavropoulos P Peter, Pereira D, Kee Hae-Young
Department of Physics and Center for Quantum Materials, University of Toronto, 60 St. George St., Toronto, Ontario, M5S 1A7, Canada.
Canadian Institute for Advanced Research, Toronto, Ontario, M5G 1Z8, Canada.
Phys Rev Lett. 2019 Jul 19;123(3):037203. doi: 10.1103/PhysRevLett.123.037203.
The spin S=1/2 Kitaev honeycomb model has attracted significant attention since emerging candidate materials have provided a playground to test non-Abelian anyons. The Kitaev model with higher spins has also been theoretically studied, as it may offer another path to a quantum spin liquid. However, a microscopic route to achieve higher spin Kitaev models in solid state materials has not been rigorously derived. Here we present a theory of the spin S=1 Kitaev interaction in two-dimensional edge-shared octahedral systems. Essential ingredients are strong spin-orbit coupling in anions and strong Hund's coupling in transition metal cations. The S=1 Kitaev and ferromagnetic Heisenberg interactions are generated from superexchange paths. Taking into account the antiferromagnetic Heisenberg term from direct-exchange paths, the Kitaev interaction dominates the physics of the S=1 system. Using an exact diagonalization technique, we show a finite regime of S=1 spin liquid in the presence of the Heisenberg interaction. Candidate materials are proposed, and generalization to higher spins is discussed.
自出现的候选材料为测试非阿贝尔任意子提供了一个平台以来，自旋S = 1/2的Kitaev蜂窝模型受到了广泛关注。具有更高自旋的Kitaev模型也已在理论上得到研究，因为它可能为量子自旋液体提供另一条途径。然而，尚未严格推导出在固态材料中实现更高自旋Kitaev模型的微观途径。在此，我们提出了一种关于二维边缘共享八面体系统中自旋S = 1的Kitaev相互作用的理论。其基本要素是阴离子中的强自旋轨道耦合和过渡金属阳离子中的强洪德耦合。S = 1的Kitaev和铁磁海森堡相互作用由超交换路径产生。考虑到直接交换路径产生的反铁磁海森堡项，Kitaev相互作用主导了S = 1系统的物理性质。使用精确对角化技术，我们展示了在存在海森堡相互作用的情况下S = 1自旋液体的有限区域。我们提出了候选材料，并讨论了向更高自旋的推广。
