论文标题
轻松平面和易于轴的角色xxz各向异性和债券交替在沮丧的铁磁旋转中 - $ 1/2 $链
Roles of easy-plane and easy-axis XXZ anisotropy and bond alternation on a frustrated ferromagnetic spin-$1/2$ chain
论文作者
论文摘要
带有铁磁的第一邻居交换耦合$ J_1 $和一个反铁磁性第二个neighbor $ J_2 $的旋转$ 1/2 $ HEISENBERG连锁店具有Haldane Dimer dimer基态状态，并具有极小的旋转缝隙。因此，基态很容易被扰动改变。在这里，我们研究了易于轴和易于平面类型的XXZ交换磁各向异性的影响，以及$ j_1 $的交替在基态，自旋间隙以及沮丧的铁磁旋转$ 1/2 $链的磁性上。发现有两个不同的二聚体自旋差阶段，其中一个旋转间隙和磁敏感性在SU（2）对称情况周围非常小，而在另一个情况下，它们距离SU（2）对称情况很大。 $ j_1 $的一个小交替迅速缩短了旋转相关性向四旋转周期性的音调，例如$ j_1/j_2 \ to0 $的极限。这些效果不足以定量解释总体实验观察到的磁性特性中的磁性磁性磁性磁电蛋白铜RB $ _2 $ _2 $ _2 $ _2 $ MO $ _3 $ _3 $ o $ $ $ $ _ {12} $，表现出磁场稳定的Ferroelectricity。我们的结果也与CS $ _2 $ CU $ _2 $ MO $ _3 $ _3 $ o $ _ {12} $有关，该$最近在单个链级中发现了Ferromagnetic Intrachain和Antromagnetic Intrachain和Anterfiromagnetic Inter链顺序。我们还通过映射到有效的自旋-1链模型中，揭示了模型中受对称保护的拓扑相变的性质。
The spin-$1/2$ Heisenberg chain with a ferromagnetic first-neighbor exchange coupling $J_1$ and an antiferromagnetic second-neighbor $J_2$ has a Haldane dimer ground state with an extremely small spin gap. Thus, the ground state is readily altered by perturbations. Here, we investigate the effects of XXZ exchange magnetic anisotropy of both the easy-axis and easy-plane types and an alternation in $J_1$ on the ground state, the spin gap, and magnetic properties of the frustrated ferromagnetic spin-$1/2$ chain. It is found that there are two distinct dimerized spin-gap phases, in one of which the spin gap and the magnetic susceptibility are extremely small around the SU(2) symmetric case and in the other they are moderately large far away from the SU(2) symmetric case. A small alternation in the amplitude of $J_1$ rapidly shortens the pitch of spin correlations towards the four-spin periodicity, as in the limit of $J_1/J_2\to0$. These effects are not sufficient to quantitatively explain overall experimentally observed magnetic properties in the quasi-one-dimensional spin-gapped magnetoelectric cuprate Rb$_2$Cu$_2$Mo$_3$O$_{12}$ that exhibits ferroelectricity stabilized by a magnetic field. Our results are also relevant to Cs$_2$Cu$_2$Mo$_3$O$_{12}$, where the ferromagnetic intrachain and antiferromagnetic interchain order has recently been found, in a single chain level. We also reveal the nature of symmetry-protected topological phase transitions in the model by mapping onto effective spin-1 chain models.
