论文标题
抗铁磁性Kitaev模型中Majorana旋转液体的现场稳定性
Field stability of Majorana spin liquids in antiferromagnetic Kitaev models
论文作者
论文摘要
磁场可以引起基塔夫自旋系统中的大量现象，例如在两个和三个空间维度中形成非平凡的自旋液体。对于原始的蜂窝基塔伊夫模型，最近观察到，键合交换的迹象对于现场诱导的物理学至关重要，抗磁磁耦合引起了低场损失基塔伊夫旋转液体之间的中间旋转液体状态，这是fiellife液体和高景极化状态的模型。在这里，通过采用Majorana平均场方法沿[001]方向指向的磁场，我们提出了一项针对各种两个和三维晶格几何形状的场诱导的自旋液相的系统研究。我们发现，抗铁磁耦合通常会导致（i）（i）旋转液相在田间比铁磁耦合的液相稳定得多，并且（ii）中间自旋液相是由Majorana带结构拓扑的变化而产生的。对平均场参数的仔细检查表明，由于“有效” $ z $ - 键 - 键参数的场驱动符号变化，发生了中间相。我们的结果清楚地表明了与铁磁磁性对应物相比，抗磁磁性Kitaev模型的大量物理学的丰富性。
Magnetic fields can give rise to a plethora of phenomena in Kitaev spin systems, such as the formation of non-trivial spin liquids in two and three spatial dimensions. For the original honeycomb Kitaev model, it has recently been observed that the sign of the bond-directional exchange is of crucial relevance for the field-induced physics, with antiferromagnetic couplings giving rise to an intermediate spin liquid regime between the low-field gapped Kitaev spin liquid and the high-field polarized state, which is not present in the ferromagnetically coupled model. Here, by employing a Majorana mean-field approach for a magnetic field pointing along the [001] direction, we present a systematic study of field-induced spin liquid phases for a variety of two and three-dimensional lattice geometries. We find that antiferromagnetic couplings generically lead to (i) spin liquid phases that are considerably more stable in field than those for ferromagnetic couplings, and (ii) an intermediate spin liquid phase which arises from a change in the topology of the Majorana band structure. Close inspection of the mean-field parameters reveal that the intermediate phase occurs due to a field-driven sign change in an 'effective' $z$-bond energy parameter. Our results clearly demonstrate the richness of the Majorana physics of the antiferromagnetic Kitaev models, in comparison to their ferromagnetic counterparts.
