论文标题
量子自旋霍尔绝缘子中两个局部旋转之间的磁相关性
Magnetic correlation between two local spins in a quantum spin Hall insulator
论文作者
论文摘要
位于量子自旋霍尔绝缘子边缘的两个自旋可以通过螺旋边缘状态介导的间接自旋交互相互作用相互作用，即rkky相互作用，可以通过两个自旋之间的磁相关来测量。通过新开发的自然轨道重新归一化组（NORG）方法，我们研究了基于在有限的Zigzag石墨烯纳米替伯恩与旋转轨道辅助（SOC）中定义的Kane-Mele模型（SOC）中定义的两个近杂质杂质与螺旋边缘状态相互作用的磁相关性。我们发现SOC效应打破了磁相关的空间分布中的对称性，从而导致rkky相互作用的各向异性。具体而言，当两种杂质位于同一sublattice时，总相关始终是铁磁性（FM），而在不同的sublattices处时始终是抗磁磁性（AFM）。同时，面内相关的行为与总相关的行为一致。但是，可以通过操纵近托耦合或爆发距离来调节平面外相关性。此外，磁相关性是可以通过SOC调谐的，尤其是可以通过增加SOC强度从FM到AFM调整平面外相关性。最终探索了由自旋stager的激发光谱和两个杂质位点的自旋stagrage敏感性表示的系统的动态特性。结果表明，当两种杂质位于不同的sublattices与在同一sublattice上的不同sublattices处时，旋转式的敏感性更大，这与平面外相关的行为一致。另一方面，我们的研究进一步表明，NORG是研究量子杂质系统的有效数值方法。
Two spins located at the edge of a quantum spin Hall insulator may interact with each other via indirect spin-exchange interaction mediated by the helical edge states, namely the RKKY interaction, which can be measured by the magnetic correlation between the two spins. By means of the newly developed natural orbitals renormalization group (NORG) method, we investigated the magnetic correlation between two Kondo impurities interacting with the helical edge states, based on the Kane-Mele model defined in a finite zigzag graphene nanoribbon with spin-orbital coupling (SOC). We find that the SOC effect breaks the symmetry in spatial distribution of the magnetic correlation, leading to anisotropy in the RKKY interaction. Specifically, the total correlation is always ferromagnetic (FM) when the two impurities are located at the same sublattice, while it is always antiferromagnetic (AFM) when at the different sublattices. Meanwhile, the behavior of the in-plane correlation is consistent with that of the total correlation. However, the out-of-plane correlation can be tuned from FM to AFM by manipulating either the Kondo coupling or the interimpurity distance. Furthermore, the magnetic correlation is tunable by the SOC, especially that the out-of-plane correlation can be adjusted from FM to AFM by increasing the strength of SOC. Dynamic properties of the system, represented by the spin-staggered excitation spectrum and the spin-staggered susceptibility at the two impurity sites, are finally explored. It is shown that the spin-staggered susceptibility is larger when the two impurities are located at the different sublattices than at the same sublattice, which is consistent with the behavior of the out-of-plane correlation. On the other hand, our study further demonstrates that the NORG is an effective numerical method for studying the quantum impurity systems.
