论文标题
在Fisher Lattice的Heisenberg模型中以沮丧的Heisenberg模型竞争订单
Competing orders in a frustrated Heisenberg model on the Fisher lattice
论文作者
论文摘要
我们在临时零件$ j_ {1} $，第二个neighbor $ j_ {2} $和第三个neighbor $ j_ {3} $交换couplings的情况下，在装饰正方形（Fisher）晶格上研究了海森堡模型。在Luttinger-Tisza框架内获得的经典地面相图由两个抗磁性有序相位，以及无限退化的抗磁磁性链相。采用经典的蒙特卡洛模拟，我们表明热波动无法提高抗铁磁链阶段的退化。有趣的是，Néel状态的自旋波谱显示了三个Dirac节点环，其中两个是对称性的，而对于反铁磁性链相，我们找到了对称性保护的DIRAC线。此外，我们研究了自旋$ s = \ frac {1} {2} $限制了使用债券运算符形式主义，该债券运算符捕获了单线 - 三重动力学，并找到丰富的地面相位图主机，除了除抗磁性订购的阶段外，还可以将各种价值债券键寄主到各种价值债券固体订单。
We investigate the Heisenberg model on a decorated square (Fisher) lattice in the presence of first-neighbor $J_{1}$, second-neighbor $J_{2}$, and third-neighbor $J_{3}$ exchange couplings, with antiferromagnetic $J_{1}$. The classical ground-state phase diagram obtained within a Luttinger-Tisza framework is spanned by two antiferromagnetically ordered phases, and an infinitely degenerate antiferromagnetic chain phase. Employing classical Monte Carlo simulations we show that thermal fluctuations fail to lift the degeneracy of the antiferromagnetic chain phase. Interestingly, the spin-wave spectrum of the Néel state displays three Dirac nodal loops out of which two are symmetry protected while for the antiferromagnetic chain phase we find symmetry-protected Dirac lines. Furthermore, we investigate the spin $S=\frac{1}{2}$ limit employing a bond operator formalism which captures the singlet-triplet dynamics, and find a rich ground-state phase diagram host to a variety of valence bond solid orders in addition to antiferromagnetically ordered phases.
