Frustrated spin-1/2 J1-J2 Heisenberg ferromagnet on the square lattice studied via exact diagonalization and coupled-cluster method
Frustrated spin-1/2 J1-J2 Heisenberg ferromagnet on the square lattice studied via exact diagonalization and coupled-cluster method
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通过精确对角化和耦合簇方法研究方形晶格上的受抑自旋 1/2 J1-J2 海森堡铁磁体
DOI：
10.1103/physrevb.81.174429
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发表时间：
2010
影响因子：
3.7
通讯作者：
H. Rosner
中科院分区：
文献类型：
--
作者：
J. Richter;R. Darradi;J. Schulenburg;D. Farnell;H. Rosner
研究了具有铁磁最近邻交换j10的方形晶格上自旋1/2 J1- j2海森堡模型的基态磁序。利用耦合簇法对N = 40位的有限晶格进行高阶近似和Lanczos精确对角化，计算了基态能量、自旋-自旋相关函数和磁序参数。我们发现铁磁基态消失的拐点由jc1 2 = 0.393jJ1j（精确对角化）和jc1 2 = 0.394jJ1j（耦合簇法）给出。我们将铁磁性J1的结果与具有反铁磁性J1的自旋1/2 J1- j2海森堡模型的结果进行了比较。我们发现两种模型（即铁磁和反铁磁J1）对于大J2的行为相似，尽管在J2/jJ1j中观察到它们之间的显着差异。0.6. 虽然对于反铁磁J1，半经典共线磁长程阶在jc2 2′0.6J1处被击穿，但对于具有铁磁J1的模型，我们直到J2′0.4 jj1j才发现类似的这种长程阶的击穿。与反铁磁J1不同的是，如果铁磁J1在具有半经典共线条纹有序和铁磁有序的相之间确实存在中间无序相，那么它很可能在J2 0.4jJ1j以下的很小范围内。
We investigate the ground-state magnetic order of the spin-1/2 J1-J2 Heisenberg model on the square lattice with ferromagnetic nearest-neighbor exchange J1 0. We use the coupled-cluster method to high orders of approximation and Lanczos exact diagonalization of finite lattices of up to N = 40 sites in order to calculate the ground-state energy, the spin-spin correlation functions, and the magnetic order parameter. We find that the transition point at which the ferromagnetic ground state disappears is given by J c1 2 = 0.393jJ1j(exact diagonalization) and J c1 2 = 0.394jJ1j(coupled-cluster method). We compare our results for ferromagnetic J1 with established results for the spin-1/2 J1-J2 Heisenberg model with antiferromagnetic J1. We find that both models (i.e., ferro- and antiferromagnetic J1) behave similarly for large J2, although significant differences between them are observed for J2/jJ1j. 0.6. Although the semiclassical collinear magnetic long-range order breaks down at J c2 2 � 0.6J1 for antiferromagnetic J1, we do not find a similar breakdown of this kind of long-range order until J2 � 0.4jJ1jfor the model with ferromagnetic J1. Unlike the case for antiferromagnetic J1, if an intermediate disordered phase does occur between the phases exhibiting semiclassical collinear stripe order and ferromagnetic order for ferromagnetic J1 then it is likely to be over a very small range below J2 � 0.4jJ1j.
方晶格受挫铁磁体中的自旋相关性和交换
DOI：
10.1209/0295-5075/88/57005
发表时间：
2009
期刊：
EPL (Europhysics Letters)
影响因子：
--
作者：
Skoulatos M
通讯作者：
Skoulatos M