自旋为1/2的双层平方晶格阻挫模型的基态相变

Ground state phase transition of spin-1/2 frustration model on stacked square lattice

基于线性自旋波理论,研究了二维各向异性双层平方晶格阻挫模型的基态性质.探讨了各向异性和自旋间交换作用对基态相图及系统可能发生相变的影响.结果显示:对于各向同性,当层间耦合相互作用J_(c)≥0.21或J_(c)≤-0.175时,Neel态(NS)和Collinear态(CS)能共存;对于各向异性,NS和CS也可以共存.对弱的各向异性,NS更稳定;对于强的各向异性,系统将发生由NS向CS转换的一阶相变.

In this paper,we investigate the ground state phase transition of the spin-1/2 frustrated model on a stacked square lattice by the linear spin wave method.The effects of the anisotropy and the interplay of neighboring couplings on phase diagram and phase transformation between the Neel state and collinear state are explored.Our results show that both the Neel state and collinear state can exist due to the interplay of interlayer coupling J_(c)≥0.21 or J_(c)≤-0.175 for an isotropic system.For an anisotropic system,both the Neel state and collinear state may also exist.In this case,for the weak anisotropy,the Neel state is more stable.For the strong anisotropy,the system will undergo a first-order phase transition from the Nèel state to the collinear state.