论文标题
Spin-1/2 $ J_1 $ - $ J_2 $型号的动力学的三角晶格
Dynamics of spin-1/2 $J_1$-$J_2$ model on the triangular lattice
论文作者
论文摘要
我们讨论旋转 - $ \ frac12 $ $ j_1 $ - $ j_2 $模型在三角晶格上使用最近提议的债券运营商理论（BOT）。与先前对该系统的讨论一致，我们在$ J_2 $增加时获得了四个阶段：具有$ 120^\ circ $订购的阶段，三个sublattices，旋转液体阶段，带有胶质条纹顺序的状态和螺旋相。详细讨论了$ 120^\ Circ $和条纹阶段。该模型的所有计算出的静态特征都与先前的数值发现非常吻合。在$ 120^\ Circ $相位中，我们观察到旋转液相时，我们观察到准颗粒光谱和动态结构因子（DSF）的演变。使用该机器人，首先在我们对该系统的$ j_2 = 0 $的研究中首先引入了一些考虑的基本激发。在条纹阶段，我们观察到，从自旋波理论（SWT）中已知的双重变性磁化光谱被量子波动分开，这些量子波动在机器人中更准确地考虑了。与SWT在条纹状态下的其他已知发现相比，我们观察到其他Spin-1和Spin-0准粒子，这些粒子在横向和纵向DSF中提供可见的异常。我们还获得了一个特殊的Spin-0准粒子，名为Singlon，他仅在四旋链相关器中产生峰值，并且在纵向DSF中是看不见的。我们表明，单次频谱位于布里鲁因区域某些地区所有Spin-0和Spin-1激发的能量以下。拉曼散射可以探测零动量处的单次频谱。
We discuss spin-$\frac12$ $J_1$--$J_2$ model on the triangular lattice using recently proposed bond-operator theory (BOT). In agreement with previous discussions of this system, we obtain four phases upon $J_2$ increasing: the phase with $120^\circ$ ordering of three sublattices, the spin-liquid phase, the state with the collinear stripe order, and the spiral phase. The $120^\circ$ and the stripe phases are discussed in detail. All calculated static characteristics of the model are in good agreement with previous numerical findings. In the $120^\circ$ phase, we observe the evolution of quasiparticles spectra and dynamical structure factors (DSFs) upon approaching the spin-liquid phase. Some of the considered elementary excitations were introduced first in our recent study of this system at $J_2=0$ using the BOT. In the stripe phase, we observe that the doubly degenerate magnon spectrum known from the spin-wave theory (SWT) is split by quantum fluctuations which are taken into account more accurately in the BOT. As compared with other known findings of the SWT in the stripe state, we observe additional spin-1 and spin-0 quasiparticles which give visible anomalies in the transverse and longitudinal DSFs. We obtain also a special spin-0 quasiparticle named singlon who produces a peak only in four-spin correlator and who is invisible in the longitudinal DSF. We show that the singlon spectrum lies below energies of all spin-0 and spin-1 excitations in some parts of the Brillouin zone. Singlon spectrum at zero momentum can be probed by the Raman scattering.
